/** * @returns whether the provided parameter is a JavaScript Array or not. */ export function isArray(array) { return Array.isArray(array); } /** * @returns whether the provided parameter is a JavaScript String or not. */ export function isString(str) { return (typeof str === 'string'); } /** * * @returns whether the provided parameter is of type `object` but **not** * `null`, an `array`, a `regexp`, nor a `date`. */ export function isObject(obj) { // The method can't do a type cast since there are type (like strings) which // are subclasses of any put not positvely matched by the function. Hence type // narrowing results in wrong results. return typeof obj === 'object' && obj !== null && !Array.isArray(obj) && !(obj instanceof RegExp) && !(obj instanceof Date); } /** * * @returns whether the provided parameter is of type `Buffer` or Uint8Array dervived type */ export function isTypedArray(obj) { const TypedArray = Object.getPrototypeOf(Uint8Array); return typeof obj === 'object' && obj instanceof TypedArray; } /** * In **contrast** to just checking `typeof` this will return `false` for `NaN`. * @returns whether the provided parameter is a JavaScript Number or not. */ export function isNumber(obj) { return (typeof obj === 'number' && !isNaN(obj)); } /** * @returns whether the provided parameter is an Iterable, casting to the given generic */ export function isIterable(obj) { return !!obj && typeof obj[Symbol.iterator] === 'function'; } /** * @returns whether the provided parameter is a JavaScript Boolean or not. */ export function isBoolean(obj) { return (obj === true || obj === false); } /** * @returns whether the provided parameter is undefined. */ export function isUndefined(obj) { return (typeof obj === 'undefined'); } /** * @returns whether the provided parameter is defined. */ export function isDefined(arg) { return !isUndefinedOrNull(arg); } /** * @returns whether the provided parameter is undefined or null. */ export function isUndefinedOrNull(obj) { return (isUndefined(obj) || obj === null); } export function assertType(condition, type) { if (!condition) { throw new Error(type ? `Unexpected type, expected '${type}'` : 'Unexpected type'); } } /** * Asserts that the argument passed in is neither undefined nor null. */ export function assertIsDefined(arg) { if (isUndefinedOrNull(arg)) { throw new Error('Assertion Failed: argument is undefined or null'); } return arg; } /** * @returns whether the provided parameter is a JavaScript Function or not. */ export function isFunction(obj) { return (typeof obj === 'function'); } export function validateConstraints(args, constraints) { const len = Math.min(args.length, constraints.length); for (let i = 0; i < len; i++) { validateConstraint(args[i], constraints[i]); } } export function validateConstraint(arg, constraint) { if (isString(constraint)) { if (typeof arg !== constraint) { throw new Error(`argument does not match constraint: typeof ${constraint}`); } } else if (isFunction(constraint)) { try { if (arg instanceof constraint) { return; } } catch (_a) { // ignore } if (!isUndefinedOrNull(arg) && arg.constructor === constraint) { return; } if (constraint.length === 1 && constraint.call(undefined, arg) === true) { return; } throw new Error(`argument does not match one of these constraints: arg instanceof constraint, arg.constructor === constraint, nor constraint(arg) === true`); } } export function getAllPropertyNames(obj) { let res = []; let proto = Object.getPrototypeOf(obj); while (Object.prototype !== proto) { res = res.concat(Object.getOwnPropertyNames(proto)); proto = Object.getPrototypeOf(proto); } return res; } export function getAllMethodNames(obj) { const methods = []; for (const prop of getAllPropertyNames(obj)) { if (typeof obj[prop] === 'function') { methods.push(prop); } } return methods; } export function createProxyObject(methodNames, invoke) { const createProxyMethod = (method) => { return function () { const args = Array.prototype.slice.call(arguments, 0); return invoke(method, args); }; }; const result = {}; for (const methodName of methodNames) { result[methodName] = createProxyMethod(methodName); } return result; } /** * Converts null to undefined, passes all other values through. */ export function withNullAsUndefined(x) { return x === null ? undefined : x; } export function assertNever(value, message = 'Unreachable') { throw new Error(message); }