feat: FakerError (#718)

Author: xDivisionByZerox

src/errors/faker-error.ts

@@ -0,0 +1,4 @@
+/**
+ * An error instance that will be thrown by faker.
+ */
+export class FakerError extends Error {}

src/fake.ts

@@ -1,4 +1,5 @@
 import type { Faker } from '.';
+import { FakerError } from './errors/faker-error';
 
 /**
  * Generator method for combining faker methods based on string input.
@@ -58,7 +59,7 @@ export class Fake {
   fake(str: string): string {
     // if incoming str parameter is not provided, return error message
     if (typeof str !== 'string' || str.length === 0) {
-      throw new Error('string parameter is required!');
+      throw new FakerError('string parameter is required!');
     }
 
     // find first matching {{ and }}
@@ -88,11 +89,11 @@ export class Fake {
     const parts = method.split('.');
 
     if (this.faker[parts[0]] == null) {
-      throw new Error('Invalid module: ' + parts[0]);
+      throw new FakerError('Invalid module: ' + parts[0]);
     }
 
     if (this.faker[parts[0]][parts[1]] == null) {
-      throw new Error('Invalid method: ' + parts[0] + '.' + parts[1]);
+      throw new FakerError('Invalid method: ' + parts[0] + '.' + parts[1]);
     }
 
     // assign the function from the module.function namespace

src/faker.ts

@@ -7,6 +7,7 @@ import { Datatype } from './datatype';
 import { _Date } from './date';
 import type { LocaleDefinition } from './definitions';
 import { DEFINITIONS } from './definitions';
+import { FakerError } from './errors/faker-error';
 import { Fake } from './fake';
 import { Finance } from './finance';
 import { Git } from './git';
@@ -83,13 +84,13 @@ export class Faker {
 
   constructor(opts: FakerOptions) {
     if (!opts) {
-      throw new Error(
+      throw new FakerError(
         'Options with at least one entry in locales must be provided'
       );
     }
 
     if (Object.keys(opts.locales ?? {}).length === 0) {
-      throw new Error(
+      throw new FakerError(
         'At least one entry in locales must be provided in the locales parameter'
       );
     }

src/finance.ts

@@ -1,4 +1,5 @@
 import type { Faker } from '.';
+import { FakerError } from './errors/faker-error';
 import type { Helpers } from './helpers';
 import ibanLib from './iban';
 
@@ -329,7 +330,7 @@ export class Finance {
     }
 
     if (!ibanFormat) {
-      throw new Error('Country code ' + countryCode + ' not supported.');
+      throw new FakerError('Country code ' + countryCode + ' not supported.');
     }
 
     let s = '';

src/index.ts

@@ -26,6 +26,7 @@ export type {
   VehicleDefinitions,
   WordDefinitions,
 } from './definitions';
+export { FakerError } from './errors/faker-error';
 export type { FakerOptions, UsableLocale, UsedLocales } from './faker';
 export { Gender } from './name';
 export type { GenderType } from './name';

src/mersenne.ts

@@ -1,3 +1,4 @@
+import { FakerError } from './errors/faker-error';
 import Gen from './utils/mersenne';
 
 /**
@@ -46,7 +47,9 @@ export class Mersenne {
    */
   seed(S: number): void {
     if (typeof S !== 'number') {
-      throw new Error('seed(S) must take numeric argument; is ' + typeof S);
+      throw new FakerError(
+        'seed(S) must take numeric argument; is ' + typeof S
+      );
     }
 
     this.gen.initGenrand(S);
@@ -60,7 +63,7 @@ export class Mersenne {
    */
   seed_array(A: number[]): void {
     if (typeof A !== 'object') {
-      throw new Error(
+      throw new FakerError(
         'seed_array(A) must take array of numbers; is ' + typeof A
       );
     }

src/random.ts

@@ -1,4 +1,5 @@
 import type { Faker } from '.';
+import { FakerError } from './errors/faker-error';
 import { deprecated } from './internal/deprecated';
 
 /**
@@ -527,7 +528,7 @@ export class Random {
     }
 
     if (charsArray.length === 0) {
-      throw new Error(
+      throw new FakerError(
         'Unable to generate string, because all possible characters are banned.'
       );
     }

src/utils/unique.ts

@@ -1,3 +1,5 @@
+import { FakerError } from '../errors/faker-error';
+
 export type RecordKey = string | number | symbol;
 
 // global results store
@@ -41,7 +43,7 @@ function errorMessage(
     now - opts.startTime,
     'ms'
   );
-  throw new Error(
+  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()'
   );

test/fake.spec.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest';
 import { faker } from '../src';
+import { FakerError } from '../src/errors/faker-error';
 
 describe('fake', () => {
   describe('fake()', () => {
@@ -32,18 +33,18 @@ describe('fake', () => {
       expect(() =>
         // @ts-expect-error: The parameter is required
         faker.fake()
-      ).toThrowError(Error('string parameter is required!'));
+      ).toThrowError(new FakerError('string parameter is required!'));
     });
 
     it('does not allow invalid module name', () => {
       expect(() => faker.fake('{{foo.bar}}')).toThrowError(
-        Error('Invalid module: foo')
+        new FakerError('Invalid module: foo')
       );
     });
 
     it('does not allow invalid method name', () => {
       expect(() => faker.fake('{{address.foo}}')).toThrowError(
-        Error('Invalid method: address.foo')
+        new FakerError('Invalid method: address.foo')
       );
     });
 

test/faker.spec.ts

@@ -1,5 +1,6 @@
 import { beforeEach, describe, expect, it } from 'vitest';
 import { faker, Faker } from '../src';
+import { FakerError } from '../src/errors/faker-error';
 
 describe('faker', () => {
   beforeEach(() => {
@@ -12,7 +13,9 @@ describe('faker', () => {
         // @ts-expect-error: mission options
         new Faker()
     ).toThrow(
-      Error('Options with at least one entry in locales must be provided')
+      new FakerError(
+        'Options with at least one entry in locales must be provided'
+      )
     );
   });
 
@@ -22,7 +25,7 @@ describe('faker', () => {
         // @ts-expect-error: missing locales
         new Faker({})
     ).toThrow(
-      Error(
+      new FakerError(
         'At least one entry in locales must be provided in the locales parameter'
       )
     );