refactor: improve unique (#810)

Co-authored-by: ST-DDT <[email protected]>

1 files changed, 96 insertions, 77 deletions

diff --git a/src/utils/unique.ts b/src/utils/unique.ts
index 2679b3d8..4e7fadce 100644
--- a/src/utils/unique.ts
+++ b/src/utils/unique.ts
@@ -2,21 +2,30 @@ import { FakerError } from '../errors/faker-error';
 
 export type RecordKey = string | number | symbol;
 
-// global results store
-// currently uniqueness is global to entire faker instance
-// this means that faker should currently *never* return duplicate values across all API methods when using `Faker.unique`
-// it's possible in the future that some users may want to scope found per function call instead of faker instance
-const found: Record<RecordKey, RecordKey> = {};
-
-// global exclude list of results
-// defaults to nothing excluded
-const exclude: RecordKey[] = [];
-
-// current iteration or retries of unique.exec ( current loop depth )
+/**
+ * Global store of unique values.
+ * This means that faker should *never* return duplicate values across all API methods when using `Faker.unique`.
+ */
+const GLOBAL_UNIQUE_STORE: Record<RecordKey, RecordKey> = {};
+
+/**
+ * Global exclude list of results.
+ * Defaults to nothing excluded.
+ */
+const GLOBAL_UNIQUE_EXCLUDE: RecordKey[] = [];
+
+/**
+ * Current iteration or retries of `unique.exec` (current loop depth).
+ */
 const currentIterations = 0;
 
-// uniqueness compare function
-// default behavior is to check value as key against object hash
+/**
+ * Uniqueness compare function.
+ * Default behavior is to check value as key against object hash.
+ *
+ * @param obj The object to check.
+ * @param key The key to check.
+ */
 function defaultCompare(
   obj: Record<RecordKey, RecordKey>,
   key: RecordKey
@@ -27,100 +36,110 @@ function defaultCompare(
   return 0;
 }
 
-// common error handler for messages
-function errorMessage(
-  now: number,
-  code: string,
-  opts: { startTime: number }
-): never {
-  console.error('error', code);
+/**
+ * Logs the given code as an error and throws it.
+ * Also logs a message for helping the user.
+ *
+ * @param startTime The time the execution started.
+ * @param now The current time.
+ * @param code The error code.
+ *
+ * @throws The given error code with additional text.
+ */
+function errorMessage(startTime: number, now: number, code: string): never {
+  console.error('Error', code);
   console.log(
-    'found',
-    Object.keys(found).length,
-    'unique entries before throwing error. \nretried:',
-    currentIterations,
-    '\ntotal time:',
-    now - opts.startTime,
-    'ms'
+    `Found ${
+      Object.keys(GLOBAL_UNIQUE_STORE).length
+    } unique entries before throwing error.
+retried: ${currentIterations}
+total time: ${now - startTime}ms`
   );
   throw new FakerError(
-    code +
-      ' for uniqueness check \n\nMay not be able to generate any more unique values with current settings. \nTry adjusting maxTime or maxRetries parameters for faker.unique()'
+    `${code} for uniqueness check.
+
+May not be able to generate any more unique values with current settings.
+Try adjusting maxTime or maxRetries parameters for faker.unique().`
   );
 }
 
+/**
+ * Generates a unique result using the results of the given method.
+ * Used unique entries will be stored internally and filtered from subsequent calls.
+ *
+ * @template Method The type of the method to execute.
+ * @param method The method used to generate the values.
+ * @param args The arguments used to call the method.
+ * @param options The optional options used to configure this method.
+ * @param options.startTime The time this execution stared. Defaults to `new Date().getTime()`.
+ * @param options.maxTime The time in milliseconds this method may take before throwing an error. Defaults to `50`.
+ * @param options.maxRetries The total number of attempts to try before throwing an error. Defaults to `50`.
+ * @param options.currentIterations The current attempt. Defaults to `0`.
+ * @param options.exclude The value or values that should be excluded/skipped. Defaults to `[]`.
+ * @param options.compare The function used to determine whether a value was already returned. Defaults to check the existence of the key.
+ */
 export function exec<Method extends (...parameters) => RecordKey>(
   method: Method,
   args: Parameters<Method>,
-  opts: {
+  options: {
+    startTime?: number;
     maxTime?: number;
     maxRetries?: number;
+    currentIterations?: number;
     exclude?: RecordKey | RecordKey[];
     compare?: (obj: Record<RecordKey, RecordKey>, key: RecordKey) => 0 | -1;
-    currentIterations?: number;
-    startTime?: number;
-  }
+  } = {}
 ): ReturnType<Method> {
   const now = new Date().getTime();
 
-  opts = opts || {};
-  opts.maxTime = opts.maxTime || 3;
-  opts.maxRetries = opts.maxRetries || 50;
-  opts.exclude = opts.exclude || exclude;
-  opts.compare = opts.compare || defaultCompare;
-
-  if (typeof opts.currentIterations !== 'number') {
-    opts.currentIterations = 0;
-  }
-
-  if (opts.startTime == null) {
-    opts.startTime = new Date().getTime();
+  const {
+    startTime = new Date().getTime(),
+    maxTime = 50,
+    maxRetries = 50,
+    compare = defaultCompare,
+  } = options;
+  let { exclude = GLOBAL_UNIQUE_EXCLUDE } = options;
+  options.currentIterations = options.currentIterations ?? 0;
+
+  // Support single exclude argument as string
+  if (!Array.isArray(exclude)) {
+    exclude = [exclude];
   }
 
-  const startTime = opts.startTime;
-
-  // support single exclude argument as string
-  if (!Array.isArray(opts.exclude)) {
-    opts.exclude = [opts.exclude];
-  }
-
-  if (opts.currentIterations > 0) {
-    // console.log('iterating', currentIterations)
-  }
+  // if (options.currentIterations > 0) {
+  //   console.log('iterating', options.currentIterations)
+  // }
 
   // console.log(now - startTime)
-  if (now - startTime >= opts.maxTime) {
-    return errorMessage(
-      now,
-      `Exceeded maxTime: ${opts.maxTime}`,
-      // @ts-expect-error: we know that opts.startTime is defined
-      opts
-    );
+  if (now - startTime >= maxTime) {
+    return errorMessage(startTime, now, `Exceeded maxTime: ${maxTime}`);
   }
 
-  if (opts.currentIterations >= opts.maxRetries) {
-    return errorMessage(
-      now,
-      `Exceeded maxRetries: ${opts.maxRetries}`,
-      // @ts-expect-error: we know that opts.startTime is defined
-      opts
-    );
+  if (options.currentIterations >= maxRetries) {
+    return errorMessage(startTime, now, `Exceeded maxRetries: ${maxRetries}`);
   }
 
-  // execute the provided method to find a potential satisfied value
+  // Execute the provided method to find a potential satisfied value.
   const result: ReturnType<Method> = method.apply(this, args);
 
-  // if the result has not been previously found, add it to the found array and return the value as it's unique
+  // If the result has not been previously found, add it to the found array and return the value as it's unique.
   if (
-    opts.compare(found, result) === -1 &&
-    opts.exclude.indexOf(result) === -1
+    compare(GLOBAL_UNIQUE_STORE, result) === -1 &&
+    exclude.indexOf(result) === -1
   ) {
-    found[result] = result;
-    opts.currentIterations = 0;
+    GLOBAL_UNIQUE_STORE[result] = result;
+    options.currentIterations = 0;
     return result;
   } else {
     // console.log('conflict', result);
-    opts.currentIterations++;
-    return exec(method, args, opts);
+    options.currentIterations++;
+    return exec(method, args, {
+      ...options,
+      startTime,
+      maxTime,
+      maxRetries,
+      compare,
+      exclude,
+    });
   }
 }