47 lines
970 B
Plaintext
47 lines
970 B
Plaintext
/**
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* Copyright (c) 2013-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @providesModule isEmpty
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* @flow
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*/
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'use strict';
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/* eslint-disable fb-www/typeof-undefined */
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/* eslint-disable no-unused-vars */
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const invariant = require("./invariant");
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/**
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* Checks if a value is empty.
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*/
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function isEmpty(value: mixed): boolean {
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if (Array.isArray(value)) {
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return value.length === 0;
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} else if (typeof value === 'object') {
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if (value) {
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invariant(!isIterable(value) || value.size === undefined, 'isEmpty() does not support iterable collections.');
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for (const _ in value) {
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return false;
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}
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}
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return true;
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} else {
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return !value;
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}
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}
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function isIterable(value: any): boolean {
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if (typeof Symbol === 'undefined') {
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return false;
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}
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return value[Symbol.iterator];
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}
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module.exports = isEmpty; |