fix: fake behavior with special replacement patterns (#688)

1 files changed, 8 insertions, 14 deletions

diff --git a/src/fake.ts b/src/fake.ts
index 854b708a..617708a6 100644
--- a/src/fake.ts
+++ b/src/fake.ts
@@ -46,32 +46,25 @@ export class Fake {
    * faker.fake('I flipped the coin an got: {{random.arrayElement(["heads", "tails"])}}') // 'I flipped the coin an got: tails'
    */
   fake(str: string): string {
-    // setup default response as empty string
-    let res = '';
-
     // if incoming str parameter is not provided, return error message
     if (typeof str !== 'string' || str.length === 0) {
       throw new Error('string parameter is required!');
     }
 
     // find first matching {{ and }}
-    const start = str.search('{{');
-    const end = str.search('}}');
+    const start = str.search(/{{[a-z]/);
+    const end = str.indexOf('}}', start);
 
     // if no {{ and }} is found, we are done
     if (start === -1 || end === -1) {
       return str;
     }
 
-    // console.log('attempting to parse', str);
-
     // extract method name from between the {{ }} that we found
     // for example: {{name.firstName}}
-    const token = str.substring(start + 2, end);
+    const token = str.substring(start + 2, end + 2);
     let method = token.replace('}}', '').replace('{{', '');
 
-    // console.log('method', method)
-
     // extract method parameters
     const regExp = /\(([^)]+)\)/;
     const matches = regExp.exec(method);
@@ -111,13 +104,14 @@ export class Fake {
 
     let result: string;
     if (typeof params === 'string' && params.length === 0) {
-      result = fn();
+      result = String(fn());
     } else {
-      result = fn(params);
+      result = String(fn(params));
     }
 
-    // replace the found tag with the returned fake value
-    res = str.replace('{{' + token + '}}', result);
+    // Replace the found tag with the returned fake value
+    // We cannot use string.replace here because the result might contain evaluated characters
+    const res = str.substring(0, start) + result + str.substring(end + 2);
 
     if (res === '') {
       return '';