chore: prefer string templates over string concatenation (#732)

25 files changed, 203 insertions, 226 deletions

diff --git a/.eslintrc.js b/.eslintrc.js
index 5423bc46..70b2861f 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -29,6 +29,7 @@ module.exports = defineConfig({
     // We may want to use this in the future
     'no-useless-escape': 'off',
     eqeqeq: ['error', 'always', { null: 'ignore' }],
+    'prefer-template': 'error',
 
     '@typescript-eslint/ban-ts-comment': 'warn',
     '@typescript-eslint/consistent-type-imports': 'error',
diff --git a/scripts/apidoc/apiDocsWriter.ts b/scripts/apidoc/apiDocsWriter.ts
index f712e4aa..cb803499 100644
--- a/scripts/apidoc/apiDocsWriter.ts
+++ b/scripts/apidoc/apiDocsWriter.ts
@@ -64,7 +64,7 @@ export function writeApiDocsModulePage(
 
   content = vitePressInFileOptions + formatMarkdown(content);
 
-  writeFileSync(resolve(pathOutputDir, lowerModuleName + '.md'), content);
+  writeFileSync(resolve(pathOutputDir, `${lowerModuleName}.md`), content);
 }
 
 /**
@@ -87,7 +87,7 @@ export function writeApiDocsDirectPage(methodName: string): void {
 
   content = vitePressInFileOptions + formatMarkdown(content);
 
-  writeFileSync(resolve(pathOutputDir, methodName + '.md'), content);
+  writeFileSync(resolve(pathOutputDir, `${methodName}.md`), content);
 }
 
 /**
@@ -111,7 +111,7 @@ export const ${lowerModuleName}: Method[] = ${JSON.stringify(
 
   contentTs = formatTypescript(contentTs);
 
-  writeFileSync(resolve(pathOutputDir, lowerModuleName + '.ts'), contentTs);
+  writeFileSync(resolve(pathOutputDir, `${lowerModuleName}.ts`), contentTs);
 }
 
 /**
diff --git a/scripts/apidoc/signature.ts b/scripts/apidoc/signature.ts
index 0341d7c0..704c4dad 100644
--- a/scripts/apidoc/signature.ts
+++ b/scripts/apidoc/signature.ts
@@ -29,7 +29,7 @@ export function prettifyMethodName(method: string): string {
 export function toBlock(comment?: Comment): string {
   return (
     (comment?.shortText.trim() || 'Missing') +
-    (comment?.text ? '\n\n' + comment.text : '')
+    (comment?.text ? `\n\n${comment.text}` : '')
   );
 }
 
@@ -116,11 +116,11 @@ export function analyzeSignature(
     try {
       let example = JSON.stringify(faker[moduleName][methodName]());
       if (example.length > 50) {
-        example = example.substring(0, 47) + '...';
+        example = `${example.substring(0, 47)}...`;
       }
 
       examples += `faker.${moduleName}.${methodName}()`;
-      examples += (example ? ` // => ${example}` : '') + '\n';
+      examples += `${example ? ` // => ${example}` : ''}\n`;
     } catch (error) {
       // Ignore the error => hide the example call + result.
     }
@@ -131,7 +131,7 @@ export function analyzeSignature(
       .map((tag) => tag.text.trimEnd()) || [];
 
   if (exampleTags.length > 0) {
-    examples += exampleTags.join('\n').trim() + '\n';
+    examples += `${exampleTags.join('\n').trim()}\n`;
   }
 
   const seeAlsos =
@@ -140,13 +140,15 @@ export function analyzeSignature(
       .map((t) => t.text.trim()) ?? [];
 
   const prettyMethodName = prettifyMethodName(methodName);
+  const code = '```';
+
   return {
     name: methodName,
     title: prettyMethodName,
     description: mdToHtml(toBlock(signature.comment)),
     parameters: parameters,
     returns: typeToText(signature.type),
-    examples: mdToHtml('```ts\n' + examples + '```'),
+    examples: mdToHtml(`${code}ts\n${examples}${code}`),
     deprecated: signature.comment?.hasTag('deprecated') ?? false,
     seeAlsos,
   };
@@ -164,10 +166,10 @@ function analyzeParameter(parameter: ParameterReflection): {
 
   let signatureText = '';
   if (defaultValue) {
-    signatureText = ' = ' + defaultValue;
+    signatureText = ` = ${defaultValue}`;
   }
 
-  const signature = declarationName + ': ' + typeToText(type) + signatureText;
+  const signature = `${declarationName}: ${typeToText(type)}${signatureText}`;
 
   const parameters: MethodParameter[] = [
     {
@@ -256,27 +258,28 @@ function declarationTypeToText(
   switch (declaration.kind) {
     case ReflectionKind.Method:
       return signatureTypeToText(declaration.signatures[0]);
+
     case ReflectionKind.Property:
       return typeToText(declaration.type);
+
     case ReflectionKind.TypeLiteral:
       if (declaration.children?.length) {
         if (short) {
           // This is too long for the parameter table, thus we abbreviate this.
           return '{ ... }';
         }
-        return (
-          '{' +
-          declaration.children
-            .map((c) => `\n${c.name}: ${declarationTypeToText(c)}`)
-            .join()
-            .replace(/\n/g, '\n  ') +
-          '\n}'
-        );
+
+        const list = declaration.children
+          .map((c) => `  ${c.name}: ${declarationTypeToText(c)}`)
+          .join(',\n');
+
+        return `{\n${list}\n}`;
       } else if (declaration.signatures?.length) {
         return signatureTypeToText(declaration.signatures[0]);
       } else {
         return declaration.toString();
       }
+
     default:
       return declaration.toString();
   }
diff --git a/scripts/generateLocales.ts b/scripts/generateLocales.ts
index f4c1f50d..38715b97 100644
--- a/scripts/generateLocales.ts
+++ b/scripts/generateLocales.ts
@@ -101,7 +101,7 @@ function generateLocaleFile(locale: string): void {
       `;
 
   content = format(content, prettierTsOptions);
-  writeFileSync(resolve(pathLocale, locale + '.ts'), content);
+  writeFileSync(resolve(pathLocale, `${locale}.ts`), content);
 }
 
 function tryLoadLocalesMainIndexFile(pathModules: string): LocaleDefinition {
@@ -253,7 +253,7 @@ function updateLocaleFileHook(
   localePath: string[]
 ): void {
   if (filePath === 'never') {
-    console.log(filePath + ' <-> ' + locale + ' @ ' + localePath.join(' -> '));
+    console.log(`${filePath} <-> ${locale} @ ${localePath.join(' -> ')}`);
   }
 }
 
@@ -285,13 +285,14 @@ for (const locale of locales) {
   generateLocaleFile(locale);
 
   // src/locales/**/index.ts
+  const separator = localeSeparator ? `\nseparator: '${localeSeparator}',` : '';
+
   generateRecursiveModuleIndexes(
     pathModules,
     locale,
     'LocaleDefinition',
     1,
-    `title: '${localeTitle}',` +
-      (localeSeparator ? `\nseparator: '${localeSeparator}',` : '')
+    `title: '${localeTitle}',${separator}`
   );
 }
 
diff --git a/scripts/verifyCommit.ts b/scripts/verifyCommit.ts
index e2c4ae70..11f22ab4 100644
--- a/scripts/verifyCommit.ts
+++ b/scripts/verifyCommit.ts
@@ -18,16 +18,22 @@ const isMergeCommit = msg.startsWith('Merge remote-tracking-branch');
 
 if (!isMergeCommit && !releaseRE.test(msg) && !commitRE.test(msg)) {
   console.log();
+
   console.error(
     `  ${colors.bgRed(colors.white(' ERROR '))} ${colors.red(
       `invalid commit message format.`
-    )}\n\n` +
-      colors.red(
-        `  Proper commit message format is required for automated changelog generation. Examples:\n\n`
-      ) +
-      `    ${colors.green(`feat: add 'comments' option`)}\n` +
-      `    ${colors.green(`fix: handle events on blur (close #28)`)}\n\n` +
-      colors.red(`  See .github/commit-convention.md for more details.\n`)
+    )}
+
+  ${colors.red(
+    `Proper commit message format is required for automated changelog generation. Examples:`
+  )}
+
+  ${colors.green(`feat: add 'comments' option`)}
+  ${colors.green(`fix: handle events on blur (close #28)`)}
+
+  ${colors.red(`See .github/commit-convention.md for more details.`)}
+`
   );
+
   process.exit(1);
 }
diff --git a/src/address.ts b/src/address.ts
index 83fa675b..e0fb6bf2 100644
--- a/src/address.ts
+++ b/src/address.ts
@@ -230,7 +230,7 @@ export class Address {
     let result: string;
     let suffix = this.streetSuffix();
     if (suffix !== '') {
-      suffix = ' ' + suffix;
+      suffix = ` ${suffix}`;
     }
 
     switch (this.faker.datatype.number(1)) {
@@ -381,7 +381,7 @@ export class Address {
       .number({
         min,
         max,
-        precision: parseFloat((0.0).toPrecision(precision) + '1'),
+        precision: parseFloat(`${(0.0).toPrecision(precision)}1`),
       })
       .toFixed(precision);
   }
@@ -406,7 +406,7 @@ export class Address {
       .number({
         max: max,
         min: min,
-        precision: parseFloat((0.0).toPrecision(precision) + '1'),
+        precision: parseFloat(`${(0.0).toPrecision(precision)}1`),
       })
       .toFixed(precision);
   }
diff --git a/src/commerce.ts b/src/commerce.ts
index a94d7b85..9d0a5731 100644
--- a/src/commerce.ts
+++ b/src/commerce.ts
@@ -45,13 +45,7 @@ export class Commerce {
    * faker.commerce.productName() // 'Incredible Soft Gloves'
    */
   productName(): string {
-    return (
-      this.productAdjective() +
-      ' ' +
-      this.productMaterial() +
-      ' ' +
-      this.product()
-    );
+    return `${this.productAdjective()} ${this.productMaterial()} ${this.product()}`;
   }
 
   /**
diff --git a/src/datatype.ts b/src/datatype.ts
index 29a4950b..90211b69 100644
--- a/src/datatype.ts
+++ b/src/datatype.ts
@@ -243,7 +243,7 @@ export class Datatype {
       ]);
     }
 
-    return '0x' + wholeString;
+    return `0x${wholeString}`;
   }
 
   /**
diff --git a/src/fake.ts b/src/fake.ts
index d478d01e..4a22e2ff 100644
--- a/src/fake.ts
+++ b/src/fake.ts
@@ -89,11 +89,11 @@ export class Fake {
     const parts = method.split('.');
 
     if (this.faker[parts[0]] == null) {
-      throw new FakerError('Invalid module: ' + parts[0]);
+      throw new FakerError(`Invalid module: ${parts[0]}`);
     }
 
     if (this.faker[parts[0]][parts[1]] == null) {
-      throw new FakerError('Invalid method: ' + parts[0] + '.' + parts[1]);
+      throw new FakerError(`Invalid method: ${parts[0]}.${parts[1]}`);
     }
 
     // assign the function from the module.function namespace
diff --git a/src/finance.ts b/src/finance.ts
index ea4174d6..2214088d 100644
--- a/src/finance.ts
+++ b/src/finance.ts
@@ -96,7 +96,7 @@ export class Finance {
     let template = '';
 
     for (let i = 0; i < length; i++) {
-      template = template + '#';
+      template = `${template}#`;
     }
 
     //prefix with ellipsis
@@ -332,7 +332,7 @@ export class Finance {
       : this.faker.random.arrayElement(iban.formats);
 
     if (!ibanFormat) {
-      throw new FakerError('Country code ' + countryCode + ' not supported.');
+      throw new FakerError(`Country code ${countryCode} not supported.`);
     }
 
     let s = '';
@@ -387,20 +387,21 @@ export class Finance {
   bic(): string {
     const vowels = ['A', 'E', 'I', 'O', 'U'];
     const prob = this.faker.datatype.number(100);
-    return (
-      this.faker.helpers.replaceSymbols('???') +
-      this.faker.random.arrayElement(vowels) +
-      this.faker.random.arrayElement(iban.iso3166) +
-      this.faker.helpers.replaceSymbols('?') +
-      '1' +
-      (prob < 10
+
+    return [
+      this.faker.helpers.replaceSymbols('???'),
+      this.faker.random.arrayElement(vowels),
+      this.faker.random.arrayElement(iban.iso3166),
+      this.faker.helpers.replaceSymbols('?'),
+      '1',
+      prob < 10
         ? this.faker.helpers.replaceSymbols(
-            '?' + this.faker.random.arrayElement(vowels) + '?'
+            `?${this.faker.random.arrayElement(vowels)}?`
           )
         : prob < 40
         ? this.faker.helpers.replaceSymbols('###')
-        : '')
-    );
+        : '',
+    ].join('');
   }
 
   /**
@@ -418,18 +419,7 @@ export class Finance {
     const company = transaction.business;
     const card = this.mask();
     const currency = this.currencyCode();
-    return (
-      transactionType +
-      ' transaction at ' +
-      company +
-      ' using card ending with ***' +
-      card +
-      ' for ' +
-      currency +
-      ' ' +
-      amount +
-      ' in account ***' +
-      account
-    );
+
+    return `${transactionType} transaction at ${company} using card ending with ***${card} for ${currency} ${amount} in account ***${account}`;
   }
 }
diff --git a/src/git.ts b/src/git.ts
index 6c82e48d..94144043 100644
--- a/src/git.ts
+++ b/src/git.ts
@@ -42,7 +42,7 @@ export class Git {
   branch(): string {
     const noun = this.faker.hacker.noun().replace(' ', '-');
     const verb = this.faker.hacker.verb().replace(' ', '-');
-    return noun + '-' + verb;
+    return `${noun}-${verb}`;
   }
 
   /**
diff --git a/src/helpers.ts b/src/helpers.ts
index 5b26bd9d..be3ce8f5 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -481,7 +481,7 @@ export class Helpers {
       return '';
     }
     for (const p in data) {
-      const re = new RegExp('{{' + p + '}}', 'g');
+      const re = new RegExp(`{{${p}}}`, 'g');
       const value = data[p];
       if (typeof value === 'string') {
         str = str.replace(re, value);
diff --git a/src/image.ts b/src/image.ts
index 2f4444ab..8aeab602 100644
--- a/src/image.ts
+++ b/src/image.ts
@@ -104,7 +104,7 @@ export class Image {
     }
     let url = `${protocol}loremflickr.com/${width}/${height}`;
     if (category != null) {
-      url += '/' + category;
+      url += `/${category}`;
     }
 
     if (randomize) {
diff --git a/src/image_providers/lorempicsum.ts b/src/image_providers/lorempicsum.ts
index 9fed741e..f28b1e8f 100644
--- a/src/image_providers/lorempicsum.ts
+++ b/src/image_providers/lorempicsum.ts
@@ -104,7 +104,7 @@ export class LoremPicsum {
     let url = 'https://picsum.photos';
 
     if (seed) {
-      url += '/seed/' + seed;
+      url += `/seed/${seed}`;
     }
 
     url += `/${width}/${height}`;
@@ -114,7 +114,7 @@ export class LoremPicsum {
     }
 
     if (grayscale) {
-      return url + '?grayscale';
+      return `${url}?grayscale`;
     }
 
     if (blur) {
diff --git a/src/image_providers/lorempixel.ts b/src/image_providers/lorempixel.ts
index 310ba45a..914f1066 100644
--- a/src/image_providers/lorempixel.ts
+++ b/src/image_providers/lorempixel.ts
@@ -67,7 +67,7 @@ export class Lorempixel {
 
     let url = `https://lorempixel.com/${width}/${height}`;
     if (category != null) {
-      url += '/' + category;
+      url += `/${category}`;
     }
 
     if (randomize) {
diff --git a/src/image_providers/unsplash.ts b/src/image_providers/unsplash.ts
index dd8abd37..994b2a04 100644
--- a/src/image_providers/unsplash.ts
+++ b/src/image_providers/unsplash.ts
@@ -59,7 +59,7 @@ export class Unsplash {
     let url = 'https://source.unsplash.com';
 
     if (category != null) {
-      url += '/category/' + category;
+      url += `/category/${category}`;
     }
 
     url += `/${width}x${height}`;
@@ -67,7 +67,7 @@ export class Unsplash {
     if (keyword != null) {
       const keywordFormat = /^([A-Za-z0-9].+,[A-Za-z0-9]+)$|^([A-Za-z0-9]+)$/;
       if (keywordFormat.test(keyword)) {
-        url += '?' + keyword;
+        url += `?${keyword}`;
       }
     }
 
diff --git a/src/internal/deprecated.ts b/src/internal/deprecated.ts
index 7f20c24f..ab67b60a 100644
--- a/src/internal/deprecated.ts
+++ b/src/internal/deprecated.ts
@@ -25,5 +25,5 @@ export function deprecated(opts: DeprecatedOptions): void {
     message += `. Please use ${opts.proposed} instead`;
   }
 
-  console.warn(message + '.');
+  console.warn(`${message}.`);
 }
diff --git a/src/internet.ts b/src/internet.ts
index 7e9b72a4..fa4ae6e8 100644
--- a/src/internet.ts
+++ b/src/internet.ts
@@ -67,9 +67,11 @@ export class Internet {
       this.faker.random.arrayElement(
         this.faker.definitions.internet.free_email
       );
+
     let localPart: string = this.faker.helpers.slugify(
       this.userName(firstName, lastName)
     );
+
     if (options?.allowSpecialCharacters) {
       const usernameChars: string[] = '._-'.split('');
       const specialChars: string[] = ".!#$%&'*+-/=?^_`{|}~".split('');
@@ -78,6 +80,7 @@ export class Internet {
         this.faker.random.arrayElement(specialChars)
       );
     }
+
     return `${localPart}@${provider}`;
   }
 
@@ -184,7 +187,7 @@ export class Internet {
    * faker.internet.url() // 'https://remarkable-hackwork.info'
    */
   url(): string {
-    return this.protocol() + '://' + this.domainName();
+    return `${this.protocol()}://${this.domainName()}`;
   }
 
   /**
@@ -194,7 +197,7 @@ export class Internet {
    * faker.internet.domainName() // 'slow-timer.info'
    */
   domainName(): string {
-    return this.domainWord() + '.' + this.domainSuffix();
+    return `${this.domainWord()}.${this.domainSuffix()}`;
   }
 
   /**
@@ -218,7 +221,7 @@ export class Internet {
    * faker.internet.domainWord() // 'weird-cytoplasm'
    */
   domainWord(): string {
-    return (this.faker.word.adjective() + '-' + this.faker.word.noun())
+    return `${this.faker.word.adjective()}-${this.faker.word.noun()}`
       .replace(/([\\~#&*{}/:<>?|\"'])/gi, '')
       .replace(/\s/g, '-')
       .replace(/-{2,}/g, '-')
@@ -316,41 +319,34 @@ export class Internet {
   }
 
   /**
-   * Generates a random css hex color code.
+   * Generates a random css hex color code in aesthetically pleasing color palette.
    *
-   * @param baseRed255 The optional base red. Used for aesthetically pleasing color palettes. Supports values between `0` and `255`. Defaults to `0`.
-   * @param baseGreen255 The optional base green. Used for aesthetically pleasing color palettes. Supports values between `0` and `255`. Defaults to `0`.
-   * @param baseBlue255 The optional base blue. Used for aesthetically pleasing color palettes. Supports values between `0` and `255`. Defaults to `0`.
+   * Based on
+   * http://stackoverflow.com/questions/43044/algorithm-to-randomly-generate-an-aesthetically-pleasing-color-palette
+   *
+   * @param redBase The optional base red in range between `0` and `255`. Defaults to `0`.
+   * @param greenBase The optional base green in range between `0` and `255`. Defaults to `0`.
+   * @param blueBase The optional base blue in range between `0` and `255`. Defaults to `0`.
    *
    * @example
    * faker.internet.color() // '#30686e'
    * faker.internet.color(100, 100, 100) // '#4e5f8b'
    */
   color(
-    baseRed255: number = 0,
-    baseGreen255: number = 0,
-    baseBlue255: number = 0
+    redBase: number = 0,
+    greenBase: number = 0,
+    blueBase: number = 0
   ): string {
-    // based on awesome response : http://stackoverflow.com/questions/43044/algorithm-to-randomly-generate-an-aesthetically-pleasing-color-palette
-    const red = Math.floor((this.faker.datatype.number(256) + baseRed255) / 2);
-    const green = Math.floor(
-      (this.faker.datatype.number(256) + baseGreen255) / 2
-    );
-    const blue = Math.floor(
-      (this.faker.datatype.number(256) + baseBlue255) / 2
-    );
-    const redStr = red.toString(16);
-    const greenStr = green.toString(16);
-    const blueStr = blue.toString(16);
-    return (
-      '#' +
-      (redStr.length === 1 ? '0' : '') +
-      redStr +
-      (greenStr.length === 1 ? '0' : '') +
-      greenStr +
-      (blueStr.length === 1 ? '0' : '') +
-      blueStr
-    );
+    const colorFromBase = (base: number): string =>
+      Math.floor((this.faker.datatype.number(256) + base) / 2)
+        .toString(16)
+        .padStart(2, '0');
+
+    const red = colorFromBase(redBase);
+    const green = colorFromBase(greenBase);
+    const blue = colorFromBase(blueBase);
+
+    return `#${red}${green}${blue}`;
   }
 
   /**
diff --git a/src/lorem.ts b/src/lorem.ts
index 103dd6a7..14cc2f6b 100644
--- a/src/lorem.ts
+++ b/src/lorem.ts
@@ -67,7 +67,7 @@ export class Lorem {
     }
 
     const sentence = this.words(wordCount);
-    return sentence.charAt(0).toUpperCase() + sentence.slice(1) + '.';
+    return `${sentence.charAt(0).toUpperCase() + sentence.slice(1)}.`;
   }
 
   /**
diff --git a/src/mersenne.ts b/src/mersenne.ts
index 21f52f6c..c8f531f2 100644
--- a/src/mersenne.ts
+++ b/src/mersenne.ts
@@ -48,7 +48,7 @@ export class Mersenne {
   seed(S: number): void {
     if (typeof S !== 'number') {
       throw new FakerError(
-        'seed(S) must take numeric argument; is ' + typeof S
+        `seed(S) must take numeric argument; is ${typeof S}`
       );
     }
 
@@ -64,7 +64,7 @@ export class Mersenne {
   seed_array(A: number[]): void {
     if (typeof A !== 'object') {
       throw new FakerError(
-        'seed_array(A) must take array of numbers; is ' + typeof A
+        `seed_array(A) must take array of numbers; is ${typeof A}`
       );
     }
 
diff --git a/src/name.ts b/src/name.ts
index b96eb8db..41a6075a 100644
--- a/src/name.ts
+++ b/src/name.ts
@@ -213,18 +213,18 @@ export class Name {
       case 0:
         prefix = this.prefix(gender);
         if (prefix) {
-          return prefix + ' ' + firstName + ' ' + lastName;
+          return `${prefix} ${firstName} ${lastName}`;
         }
       // TODO @Shinigami92 2022-01-21: Not sure if this fallthrough is wanted
       // eslint-disable-next-line no-fallthrough
       case 1:
         suffix = this.suffix();
         if (suffix) {
-          return firstName + ' ' + lastName + ' ' + suffix;
+          return `${firstName} ${lastName} ${suffix}`;
         }
     }
 
-    return firstName + ' ' + lastName;
+    return `${firstName} ${lastName}`;
   }
 
   /**
@@ -309,7 +309,7 @@ export class Name {
    * faker.name.jobTitle() // 'Global Accounts Engineer'
    */
   jobTitle(): string {
-    return this.jobDescriptor() + ' ' + this.jobArea() + ' ' + this.jobType();
+    return `${this.jobDescriptor()} ${this.jobArea()} ${this.jobType()}`;
   }
 
   /**
diff --git a/src/system.ts b/src/system.ts
index 16ddd876..05d0bf44 100644
--- a/src/system.ts
+++ b/src/system.ts
@@ -54,9 +54,9 @@ export class System {
    * faker.system.fileName() // 'self_enabling_accountability_toys.kpt'
    */
   fileName(): string {
-    let str = this.faker.random.words();
-    str = str.toLowerCase().replace(/\W/g, '_') + '.' + this.fileExt();
-    return str;
+    const str = this.faker.random.words().toLowerCase().replace(/\W/g, '_');
+
+    return `${str}.${this.fileExt()}`;
   }
 
   /**
@@ -68,10 +68,9 @@ export class System {
    * faker.system.commonFileName('txt') // 'global_borders_wyoming.txt'
    */
   commonFileName(ext?: string): string {
-    let str = this.faker.random.words();
-    str = str.toLowerCase().replace(/\W/g, '_');
-    str += '.' + (ext || this.commonFileExt());
-    return str;
+    const str = this.faker.random.words().toLowerCase().replace(/\W/g, '_');
+
+    return `${str}.${ext || this.commonFileExt()}`;
   }
 
   /**
diff --git a/src/utils/user-agent.ts b/src/utils/user-agent.ts
index 7f7e8cbb..5ff18c2a 100644
--- a/src/utils/user-agent.ts
+++ b/src/utils/user-agent.ts
@@ -267,23 +267,19 @@ export function generate(faker: Faker): string {
     firefox(arch: Arch): string {
       //https://developer.mozilla.org/en-US/docs/Gecko_user_agent_string_reference
       const firefox_ver = `${rnd(5, 15)}${randomRevision(2)}`,
-        gecko_ver = 'Gecko/20100101 Firefox/' + firefox_ver,
+        gecko_ver = `Gecko/20100101 Firefox/${firefox_ver}`,
         proc = randomProc(arch),
         os_ver =
           arch === 'win'
-            ? '(Windows NT ' + version_string.nt() + (proc ? `; ${proc}` : '')
+            ? `(Windows NT ${version_string.nt()}${proc ? `; ${proc}` : ''}`
             : arch === 'mac'
             ? `(Macintosh; ${proc} Mac OS X ${version_string.osx()}`
             : `(X11; Linux ${proc}`;
 
-      return (
-        'Mozilla/5.0 ' +
-        os_ver +
-        '; rv:' +
-        firefox_ver.slice(0, -2) +
-        ') ' +
-        gecko_ver
-      );
+      return `Mozilla/5.0 ${os_ver}; rv:${firefox_ver.slice(
+        0,
+        -2
+      )}) ${gecko_ver}`;
     },
 
     iexplorer(): string {
@@ -299,18 +295,13 @@ export function generate(faker: Faker): string {
 
       //http://msdn.microsoft.com/en-us/library/ie/ms537503(v=vs.85).aspx
       return `Mozilla/5.0 (compatible; MSIE ${ver}.0; Windows NT ${version_string.nt()}; Trident/${version_string.trident()}${
-        rnd(0, 1) === 1 ? '; .NET CLR ' + version_string.net() : ''
+        rnd(0, 1) === 1 ? `; .NET CLR ${version_string.net()}` : ''
       })`;
     },
 
     opera(arch: Arch): string {
       //http://www.opera.com/docs/history/
-      const presto_ver =
-          ' Presto/' +
-          version_string.presto() +
-          ' Version/' +
-          version_string.presto2() +
-          ')',
+      const presto_ver = ` Presto/${version_string.presto()} Version/${version_string.presto2()})`,
         os_ver =
           arch === 'win'
             ? `(Windows NT ${version_string.nt()}; U; ${randomLang()}${presto_ver}`
@@ -329,18 +320,9 @@ export function generate(faker: Faker): string {
             ? `(Macintosh; ${randomProc('mac')} Mac OS X ${version_string.osx(
                 '_'
               )} rv:${rnd(2, 6)}.0; ${randomLang()}) `
-            : '(Windows; U; Windows NT ' + version_string.nt() + ')';
+            : `(Windows; U; Windows NT ${version_string.nt()})`;
 
-      return (
-        'Mozilla/5.0 ' +
-        os_ver +
-        'AppleWebKit/' +
-        safari +
-        ' (KHTML, like Gecko) Version/' +
-        ver +
-        ' Safari/' +
-        safari
-      );
+      return `Mozilla/5.0 ${os_ver}AppleWebKit/${safari} (KHTML, like Gecko) Version/${ver} Safari/${safari}`;
     },
 
     chrome(arch: Arch): string {
@@ -351,19 +333,10 @@ export function generate(faker: Faker): string {
                 '_'
               )}) `
             : arch === 'win'
-            ? '(Windows; U; Windows NT ' + version_string.nt() + ')'
+            ? `(Windows; U; Windows NT ${version_string.nt()})`
             : `(X11; Linux ${randomProc(arch)}`;
 
-      return (
-        'Mozilla/5.0 ' +
-        os_ver +
-        ' AppleWebKit/' +
-        safari +
-        ' (KHTML, like Gecko) Chrome/' +
-        version_string.chrome() +
-        ' Safari/' +
-        safari
-      );
+      return `Mozilla/5.0 ${os_ver} AppleWebKit/${safari} (KHTML, like Gecko) Chrome/${version_string.chrome()} Safari/${safari}`;
     },
   };
 
diff --git a/test/all_functional.spec.ts b/test/all_functional.spec.ts
index a307e1fc..756749af 100644
--- a/test/all_functional.spec.ts
+++ b/test/all_functional.spec.ts
@@ -85,11 +85,11 @@ describe('functional tests', () => {
             };
 
             if (isWorkingLocaleForMethod(module, meth, locale)) {
-              it(meth + '()', testAssertion);
+              it(`${meth}()`, testAssertion);
             } else {
               // TODO ST-DDT 2022-03-28: Remove once there are no more failures
               // We expect a failure here to ensure we remove the exclusions when fixed
-              it.fails(meth + '()', testAssertion);
+              it.fails(`${meth}()`, testAssertion);
             }
           });
         });
@@ -104,11 +104,11 @@ describe('faker.fake functional tests', () => {
       Object.keys(modules).forEach((module) => {
         describe(module, () => {
           modules[module].forEach((meth) => {
-            it(meth + '()', () => {
+            it(`${meth}()`, () => {
               faker.locale = locale;
               // TODO ST-DDT 2022-03-28: Use random seed once there are no more failures
               faker.seed(1);
-              const result = faker.fake('{{' + module + '.' + meth + '}}');
+              const result = faker.fake(`{{${module}.${meth}}}`);
 
               expect(result).toBeTypeOf('string');
             });
diff --git a/test/finance_iban.spec.ts b/test/finance_iban.spec.ts
index c777e797..64de0504 100644
--- a/test/finance_iban.spec.ts
+++ b/test/finance_iban.spec.ts
@@ -49,27 +49,31 @@ describe('finance_iban', () => {
 
           expect(
             iban.substring(0, 2),
-            iban.substring(0, 2) +
-              ' must contains only characters in GE IBAN ' +
-              ibanFormatted
+            `${iban.substring(
+              0,
+              2
+            )} must contains only characters in GE IBAN ${ibanFormatted}`
           ).match(/^[A-Z]{2}$/);
           expect(
             iban.substring(2, 4),
-            iban.substring(2, 4) +
-              ' must contains only digit in GE IBAN ' +
-              ibanFormatted
+            `${iban.substring(
+              2,
+              4
+            )} must contains only digit in GE IBAN ${ibanFormatted}`
           ).match(/^\d{2}$/);
           expect(
             iban.substring(4, 6),
-            iban.substring(4, 6) +
-              ' must contains only characters in GE IBAN ' +
-              ibanFormatted
+            `${iban.substring(
+              4,
+              6
+            )} must contains only characters in GE IBAN ${ibanFormatted}`
           ).match(/^[A-Z]{2}$/);
           expect(
             iban.substring(6, 24),
-            iban.substring(6, 24) +
-              ' must contains only characters in GE IBAN ' +
-              ibanFormatted
+            `${iban.substring(
+              6,
+              24
+            )} must contains only characters in GE IBAN ${ibanFormatted}`
           ).match(/^\d{16}$/);
 
           expect(
@@ -105,27 +109,31 @@ describe('finance_iban', () => {
 
           expect(
             iban.substring(0, 2),
-            iban.substring(0, 2) +
-              ' must contains only characters in PK IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              0,
+              2
+            )} must contains only characters in PK IBAN ${ibanFormated}`
           ).match(/^[A-Z]{2}$/);
           expect(
             iban.substring(2, 4),
-            iban.substring(2, 4) +
-              ' must contains only digit in PK IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              2,
+              4
+            )} must contains only digit in PK IBAN ${ibanFormated}`
           ).match(/^\d{2}$/);
           expect(
             iban.substring(4, 8),
-            iban.substring(4, 8) +
-              ' must contains only characters in PK IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              4,
+              8
+            )} must contains only characters in PK IBAN ${ibanFormated}`
           ).match(/^[A-Z]{4}$/);
           expect(
             iban.substring(8, 24),
-            iban.substring(8, 24) +
-              ' must contains only digits in PK IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              8,
+              24
+            )} must contains only digits in PK IBAN ${ibanFormated}`
           ).match(/^\d{16}$/);
 
           expect(
@@ -167,43 +175,43 @@ describe('finance_iban', () => {
 
           expect(
             iban.substring(0, 2),
-            'Country Code:' +
-              iban.substring(0, 2) +
-              ' must contains only characters in PK IBAN ' +
-              ibanFormated
+            `Country Code:${iban.substring(
+              0,
+              2
+            )} must contains only characters in PK IBAN ${ibanFormated}`
           ).match(/^[A-Z]{2}$/);
           expect(
             iban.substring(2, 4),
-            'Control key:' +
-              iban.substring(2, 4) +
-              ' must contains only digit in PK IBAN ' +
-              ibanFormated
+            `Control key:${iban.substring(
+              2,
+              4
+            )} must contains only digit in PK IBAN ${ibanFormated}`
           ).match(/^\d{2}$/);
           expect(
             iban.substring(4, 9),
-            'Swift Bank Code:' +
-              iban.substring(4, 9) +
-              ' must contains only digits in PK IBAN ' +
-              ibanFormated
+            `Swift Bank Code:${iban.substring(
+              4,
+              9
+            )} must contains only digits in PK IBAN ${ibanFormated}`
           ).match(/^\d{5}$/);
           expect(
             iban.substring(9, 10),
-            'National Digit:' +
-              iban.substring(9, 10) +
-              ' must contains only digits in PK IBAN ' +
-              ibanFormated
+            `National Digit:${iban.substring(
+              9,
+              10
+            )} must contains only digits in PK IBAN ${ibanFormated}`
           ).match(/^\d{1}$/);
           expect(
             iban.substring(10, 26),
-            'Account Code:' +
-              iban.substring(10, 26) +
-              ' must contains only digits in PK IBAN ' +
-              ibanFormated
+            `Account Code:${iban.substring(
+              10,
+              26
+            )} must contains only digits in PK IBAN ${ibanFormated}`
           ).match(/^\d{16}$/);
 
           expect(
             iban.substring(2, 26),
-            'No character after TR ' + ibanFormated
+            `No character after TR ${ibanFormated}`
           ).match(/^\d{24}$/);
 
           expect(
@@ -237,27 +245,31 @@ describe('finance_iban', () => {
 
           expect(
             iban.substring(0, 2),
-            iban.substring(0, 2) +
-              ' must contains only characters in AZ IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              0,
+              2
+            )} must contains only characters in AZ IBAN ${ibanFormated}`
           ).match(/^[A-Z]{2}$/);
           expect(
             iban.substring(2, 4),
-            iban.substring(2, 4) +
-              ' must contains only digit in AZ IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              2,
+              4
+            )} must contains only digit in AZ IBAN ${ibanFormated}`
           ).match(/^\d{2}$/);
           expect(
             iban.substring(4, 8),
-            iban.substring(4, 8) +
-              ' must contains only characters in AZ IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              4,
+              8
+            )} must contains only characters in AZ IBAN ${ibanFormated}`
           ).match(/^[A-Z]{4}$/);
           expect(
             iban.substring(8, 28),
-            iban.substring(8, 28) +
-              ' must contains 20 characters in AZ IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              8,
+              28
+            )} must contains 20 characters in AZ IBAN ${ibanFormated}`
           ).match(/^\d{20}$/);
 
           expect(
@@ -292,16 +304,18 @@ describe('finance_iban', () => {
 
           expect(
             iban.substring(0, 2),
-            iban.substring(0, 2) +
-              "must start with 'CR' in CR IBAN " +
-              ibanFormated
+            `${iban.substring(
+              0,
+              2
+            )}must start with 'CR' in CR IBAN ${ibanFormated}`
           ).to.eq('CR');
 
           expect(
             iban.substring(2, 22),
-            iban.substring(2, 22) +
-              ' must contains only digit in AZ IBAN ' +
-              ibanFormated
+            `${iban.substring(
+              2,
+              22
+            )} must contains only digit in AZ IBAN ${ibanFormated}`
           ).match(/^\d{20}$/);
 
           expect(