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41 lines
1.2 KiB
TypeScript
41 lines
1.2 KiB
TypeScript
// Loaded from https://deno.land/x/graphql_deno@v15.0.0/lib/jsutils/isCollection.js
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import { SYMBOL_ITERATOR } from '../polyfills/symbols.js';
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/**
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* Returns true if the provided object is an Object (i.e. not a string literal)
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* and is either Iterable or Array-like.
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*
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* This may be used in place of [Array.isArray()][isArray] to determine if an
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* object should be iterated-over. It always excludes string literals and
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* includes Arrays (regardless of if it is Iterable). It also includes other
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* Array-like objects such as NodeList, TypedArray, and Buffer.
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*
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* @example
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*
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* isCollection([ 1, 2, 3 ]) // true
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* isCollection('ABC') // false
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* isCollection({ length: 1, 0: 'Alpha' }) // true
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* isCollection({ key: 'value' }) // false
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* isCollection(new Map()) // true
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*
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* @param obj
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* An Object value which might implement the Iterable or Array-like protocols.
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* @return {boolean} true if Iterable or Array-like Object.
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*/
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export default function isCollection(obj) {
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if (obj == null || typeof obj !== 'object') {
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return false;
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} // Is Array like?
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const length = obj.length;
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if (typeof length === 'number' && length >= 0 && length % 1 === 0) {
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return true;
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} // Is Iterable?
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return typeof obj[SYMBOL_ITERATOR] === 'function';
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} |