whether-is/dist/index.d.ts

A comprehensive, extensible, and type-friendly type and value checking utility for JavaScript/TypeScript.

declare class UntypedWhether extends Function {
    constructor();
    /**
     * Same as `Object.is`
     */
    is(a: any, b: any): boolean;
    /**
     * Deepl equal
     * @param a
     * @param b
     */
    equal(a: any, b: any): boolean;
    /**
     * Check if the target is **not** one of `undefined`, `null`, `+0`, `-0`, `NaN`, `0`, or `''`
     * @param o target
     */
    isTruthy(o: any): boolean;
    /**
     * Check if the target is one of `undefined`, `null`, `+0`, `-0`, `NaN`, `0`, or `''`
     * @param o target
     */
    isFalsy(o: any): boolean;
    /**
     * Returns `true` if the target is falsy or `{}`, `[]`
     * @param o target
     */
    isEmpty(o: any): boolean;
    /**
     * Check if the target has no keys
     * - return `null` if the target is not an object
     */
    isEmptyObject(o: any): boolean | null;
    /**
     * Check if the target is an empty array
     * - return `null` if the target is not an object
     */
    isEmptyArray(o: any): boolean | null;
    /**
     * Tell whether the target is negative zero
     * @param o target
     */
    isNegativeZero(o: any): boolean;
    /**
     * Tell whether the target is positive zero
     * @param o target
     */
    isPositiveZero(o: any): boolean;
    /**
     * Check if the constructor of the target has the similar properties as the given constructor
     * - Will check all property keys in the proto chain, and compare their `typeof o[key]`
     * @param protoClass
     * @param o
     * @returns
     */
    likeInstanceOf<T extends Class>(protoClass: T, o: any): o is InstanceType<T>;
    /**
     * Tell whether the target is like an `Error` instance
     * - If the target is an instanceof `Error`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * @param o target
     */
    likeError(o: any): o is Error;
    /**
     * Tell whether the target is like a `Date` instance
     * - If the target is an instanceof `Date`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * @param o target
     */
    likeDate(o: any): o is Date;
    /**
     * Tell whether the target is like a `Promise`
     * - If the target is an instanceof `Promise`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * @param o target
     */
    likePromise<T = any>(o: any): o is Promise<T>;
    /**
     * Tell whether the target is like a `Set`
     * - If the target is an instanceof `Set`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * @param o target
     */
    likeSet<T = any>(o: any): o is Set<T>;
    /**
     * Tell whether the target is like a `Map`
     * - If the target is an instanceof `Map`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * @param o target
     */
    likeMap<K = any, V = any>(o: any): o is Map<K, V>;
    /**
     * Tell whether the target is like a `WeakSet`
     * - If the target is an instanceof `WeakSet`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * - `likeWeakSet(Set)` is  **true !**
     * @param o target
     */
    likeWeakSet<T extends WeakKey>(o: any): o is WeakSet<T>;
    /**
     * Tell whether the target is like a `WeakMap`
     * - If the target is an instanceof `WeakMap`, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same `typeof`.
     * - `likeWeakMap(Map)` is  **true !**
     * @param o target
     */
    likeWeakMap<K extends WeakKey, V = any>(o: any): o is WeakMap<K, V>;
    /**
     * Tell whether the target is iterable
     * @param o target
     */
    isIterable(o: any): o is Iterable<any>;
    /**
     * Tell whether the target is a plain object (created by {} or new Object)
     * @param o target
     */
    isPlainObject(o: any): o is object;
    /**
     * Tell whether the target is like a RegExp instance
     * - If the target is an instanceof RegExp, returns true immediately.
     * - Otherwise, checks if all property keys in the prototype chain have the same typeof.
     * @param o target
     */
    likeRegExp(o: any): o is RegExp;
    /**
     * Tell whether the target is Promise-like
     *
     * Checks if the target is an object or function and has a 'then' method which is a function.
     * @param o target
     */
    isPromiseLike<T = any>(o: any): o is PromiseLike<T>;
    /**
     * Tell whether the target is a non-null object
     * @param o target
     */
    isObject<T extends object>(o: any): o is T;
    /**
     * Tell whether the target is a non-null object or a function
     * @param o target
     */
    likeObject<T extends object | Func>(o: unknown): o is T;
    /**
     * Tell whether the target is a function
     * @param o target
     */
    isFunction(o: any): o is Func;
    /**
     * Tell whether the target is a string
     * @param o target
     */
    isString(o: any): o is string;
    /**
     * Tell whether the target is a number
     * @param o target
     */
    isNumber(o: any): o is number;
    /**
     * Tell whether the target is a boolean
     * @param o target
     */
    isBoolean(o: any): o is boolean;
    /**
     * Tell whether the target is undefined
     * @param o target
     */
    isUndefined(o: any): o is undefined;
    /**
     * Tell whether the target is null
     * @param o target
     */
    isNull(o: any): o is null;
    /**
     * Tell whether the target is a symbol
     * @param o target
     */
    isSymbol(o: any): o is symbol;
    /**
     * Tell whether the target is a bigint
     * @param o target
     */
    isBigInt(o: any): o is bigint;
    /**
     * Tell whether the target is null or undefined
     * @param o target
     */
    isNullish(o: any): o is null | undefined;
    /**
     * Tell whether the target is a primitive value
     * @param o target
     */
    isPrimitive(o: any): o is string | number | boolean | null | undefined | symbol | bigint;
    /**
     * Tell whether the target is a field key (string or symbol)
     * @param o target
     */
    isField(o: unknown): o is string | symbol;
    /**
     * Tell whether the target is a property key (string, symbol or number)
     * @param o target
     */
    isPropertyKey(o: unknown): o is string | symbol | number;
    /**
     * Tell whether the target is NaN
     * - **if target is not a number, it will return `null`**
     * - if target is a number, it will return `true` if it is `NaN`
     * @param o target
     */
    isNaN(o: any): boolean | null;
    /**
     * Tell whether the target is an integer
     * @param o target
     */
    isInteger(o: any): boolean;
    /**
     * Tell whether the target is a safe integer
     * @param o target
     */
    isSafeInteger(o: any): boolean;
    /**
     * Tell whether the target is a safe number
     * @param o target
     */
    isSafeNumber(o: any): boolean;
    isFinite(o: any): boolean;
    /**
     * Tell whether the target is a class constructor
     * - use proxy to check if the target is constructable
     * - then see if `target.toString()` starts with `class` or `[class`(sometimes in node)
     * - cannot tell after `.bind()` or Proxied the apply behavior of a class
     * @see For precise results, see https://github.com/baendlorel/get-function-features
     * @param o target
     */
    isClass(o: any): o is Class;
    /**
     * Asserts that `arr` is an array.
     * - If `predicate` is provided, it will be called for each element in the array.
     *   - If it returns a string, it will throw an error with that message.
     *   - If it returns `null` or `undefined`, the element is considered valid.
     *   - If it returns `boolean` and value is `true`, the element is considered valid.
     * @param o target array
     * @param predicate function to validate each element
     * @param msg
     */
    isArray<T = any>(o: any, predicate?: (value?: T, index?: number, array?: T[]) => string | boolean): o is T[];
    /**
     * Tell whether the target is like `(...) => any`
     * - Might be not so accurate under some extreme circumstances like bound functions or proxied functions, etc.
     *   - So we just don't allow such cases.
     * @see For precise results, see https://github.com/baendlorel/get-function-features
     */
    isArrowFunction(o: any): o is Func;
    /**
     * (Optional) Tell whether the target is negative zero
     * @param o target
     */
    orNegativeZero(o: any): boolean;
    /**
     * (Optional) Tell whether the target is positive zero
     * @param o target
     */
    orPositiveZero(o: any): boolean;
    /**
     * (Optional) Tell whether the target is a function
     * @param o target
     */
    orFunction(o: any): o is Func | undefined;
    /**
     * (Optional) Tell whether the target is a non-null object
     * @param o target
     */
    orObject<T extends object>(o: any): o is T | undefined;
    /**
     * (Optional) Tell whether the target is a non-null object or a function
     * @param o target
     */
    orLikeObject(o: unknown): o is object | Func | undefined;
    /**
     * (Optional) Tell whether the target is a string
     * @param o target
     */
    orString(o: any): o is string | undefined;
    /**
     * (Optional) Tell whether the target is a number
     * @param o target
     */
    orNumber(o: any): o is number | undefined;
    /**
     * (Optional) Tell whether the target is a boolean
     * @param o target
     */
    orBoolean(o: any): o is boolean | undefined;
    /**
     * (Optional) Tell whether the target is undefined
     * @param o target
     */
    orUndefined(o: any): o is undefined;
    /**
     * (Optional) Tell whether the target is null
     * @param o target
     */
    orNull(o: any): o is null | undefined;
    /**
     * (Optional) Tell whether the target is a symbol
     * @param o target
     */
    orSymbol(o: any): o is symbol | undefined;
    /**
     * (Optional) Tell whether the target is a bigint
     * @param o target
     */
    orBigInt(o: any): o is bigint | undefined;
    /**
     * (Optional) Tell whether the target is a field key (string or symbol)
     * @param o target
     */
    orField(o: unknown): o is string | symbol | undefined;
    /**
     * (Optional) Tell whether the target is a property key (string, symbol or number)
     * @param o target
     */
    orPropertyKey(o: unknown): o is string | symbol | number | undefined;
    /**
     * (Optional) Tell whether the target is NaN
     * @param o target
     */
    orNaN(o: any): boolean | null;
    /**
     * (Optional) Tell whether the target is an integer
     * @param o target
     */
    orInteger(o: any): boolean;
    /**
     * (Optional) Tell whether the target is a safe integer
     * @param o target
     */
    orSafeInteger(o: any): boolean;
    /**
     * (Optional) Tell whether the target is a safe number
     * @param o target
     */
    orSafeNumber(o: any): boolean;
    /**
     * (Optional) Tell whether the target is a class constructor
     * @param o target
     */
    orClass(o: any): o is Class | undefined;
    /**
     * (Optional) Tell whether the target is an array
     * @param o target array
     * @param predicate function to validate each element
     */
    orArray<T = any>(o: any, predicate?: (value?: T, index?: number, array?: T[]) => string | boolean): o is T[] | undefined;
}

type Whether = (<T = any>(o: unknown) => o is T) & UntypedWhether;
/**
 * Expect the target to be truthy.
 * @param target
 */
declare const whether: Whether;

export { whether };