expect-more

Curried JavaScript Type Testing Library with Zero Dependencies

Installation

npm install expect-more --save-dev

Usage

1import { endsWith, isWithinRange } from 'expect-more';
2
3const result: boolean = endsWith('Script', 'JavaScript');
4// => true
5
6const endsWithScript = endsWith('Script');
7endsWithScript('JavaScript');
8// => true
9
10isWithinRange(10, 20, 21);
11// => false
12
13[0, 1, 1, 2, 3, 5, 8, 13, 21, 34].filter(isWithinRange(5, 15));
14// => [5, 8, 13]

API: expect-more

General

1declare const isBoolean: (value: unknown) => value is boolean;
2declare const isFalse: (value: unknown) => value is false;
3declare const isNull: (value: unknown) => value is null;
4declare const isRegExp: (value: unknown) => value is RegExp;
5declare const isTrue: (value: unknown) => value is true;
6declare const isUndefined: (value: unknown) => value is undefined;

Functions

1declare const isAsyncFunction: <T = (...args: any[]) => Promise<any>>(
2  value: unknown,
3) => value is T;
4declare const isFunction: <T = (...args: any[]) => any>(value: unknown) => value is T;
5declare const isGeneratorFunction: <T = Generator>(value: unknown) => value is T;
6declare const throwsAnyError: <T = (...args: any[]) => any>(value: unknown) => value is T;
7declare const throwsErrorOfType: <T = (...args: any[]) => any>(
8  typeName: string,
9  value: unknown,
10) => value is T;

Objects

1declare const hasMember: <T = any>(memberName: string, value: unknown) => value is T;
2declare const isEmptyObject: <T = any>(value: unknown) => value is T;
3declare const isNil: (value: unknown) => value is undefined | null;
4declare const isNonEmptyObject: <T = any>(value: unknown) => value is T;
5declare const isObject: <T = any>(value: unknown) => value is T;
6declare const isWalkable: <T = any>(value: unknown) => value is T;

Arrays

1declare const isArray: <T extends any[] = any[]>(value: unknown) => value is T;
2declare const isArrayIncludingAllOf: <T extends any[] = any[]>(needed: any[], value: unknown) => value is T;
3declare const isArrayIncludingAnyOf: <T extends any[] = any[]>(needed: any[], value: unknown) => value is T;
4declare const isArrayIncludingOnly: <T extends any[] = any[]>(needed: any[], value: unknown) => value is T;
5declare const isArrayOfBooleans: (value: unknown) => value is boolean[];
6declare const isArrayOfNumbers: (value: unknown) => value is number[];
7declare const isArrayOfObjects: <T extends any[] = any[]>(value: unknown) => value is T;
8declare const isArrayOfSize: <T extends any[] = any[]>(
9  size: number,
10  value: unknown,
11) => value is T;
12declare const isArrayOfStrings: (value: unknown) => value is string[];
13declare const isEmptyArray: <T extends [] = []>(any) => value is T;
14declare const isNonEmptyArray: <T extends any[] = any[]>(value: unknown) => value is T;

Dates

1declare const isAfter: (other: Date, value: unknown) => value is Date;
2declare const isBefore: (other: Date, value: unknown) => value is Date;
3declare const isDate: (value: unknown) => value is Date;
4declare const isDateBetween: (floor: Date, ceiling: Date, value: unknown) => value is Date;
5declare const isDateInMonth: (index: number, value: unknown) => value is Date;
6declare const isDateInYear: (year: number, value: unknown) => value is Date;
7declare const isDateOnDayOfMonth: (day: number, value: unknown) => value is Date;
8declare const isDateOnDayOfWeek: (index: number, value: unknown) => value is Date;
9declare const isDateOnOrAfter: (other: Date, value: unknown) => value is Date;
10declare const isDateOnOrBefore: (other: Date, value: unknown) => value is Date;
11declare const isValidDate: (value: unknown) => value is Date;

Numbers

1declare const isCalculable: (value: unknown) => value is number;
2declare const isDecimalNumber: (value: unknown) => value is number;
3declare const isDivisibleBy: (other: number, value: unknown) => value is number;
4declare const isEvenNumber: (value: unknown) => value is number;
5declare const isGreaterThanOrEqualTo: (other: number, value: unknown) => value is number;
6declare const isLessThanOrEqualTo: (other: number, value: unknown) => value is number;
7declare const isNear: (other: number, epsilon: number, value: unknown) => value is number;
8declare const isNegativeNumber: (value: unknown) => value is number;
9declare const isNumber: (value: unknown) => value is number;
10declare const isOddNumber: (value: unknown) => value is number;
11declare const isPositiveNumber: (value: unknown) => value is number;
12declare const isWholeNumber: (value: unknown) => value is number;
13declare const isWithinRange: (
14  floor: number,
15  ceiling: number,
16  value: unknown,
17) => value is number;

Strings

1declare const endsWith: (other: string, value: unknown) => value is string;
2declare const isEmptyString: (value: unknown) => value is string;
3declare const isIso8601: (value: unknown) => value is string;
4declare const isJsonString: (value: unknown) => value is string;
5declare const isLongerThan: (other: string, value: unknown) => value is string;
6declare const isNonEmptyString: (value: unknown) => value is string;
7declare const isSameLengthAs: (other: string, value: unknown) => value is string;
8declare const isShorterThan: (other: string, value: unknown) => value is string;
9declare const isString: (value: unknown) => value is string;
10declare const isVisibleString: (value: unknown) => value is string;
11declare const isWhitespace: (value: unknown) => value is string;
12declare const startsWith: (other: string, value: unknown) => value is string;

API: expect-more/gen

1declare const withMissingBranches: (value: object | any[]) => Generator;
2declare const withMissingLeaves: (value: object | any[]) => Generator;
3declare const withMissingNodes: (value: object | any[]) => Generator;
4declare const withNullBranches: (value: object | any[]) => Generator;
5declare const withNullLeaves: (value: object | any[]) => Generator;
6declare const withNullNodes: (value: object | any[]) => Generator;