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b36f21cbaf
Faster/simpler isPlainObject check. This runs up the prototype chain to check equivalency. When run in a cross-realm environment (differing contexts, iframes, etc), this ensures we're checking the value's prototype matches its context-specific instance of Object. This is faster than calling `toString()` on the constructor. There's still the `baseGetTag()` call, which does its own `toString()`, but this swaps out one for cross-realm stuff. It's also a bit simpler to understand, I think.
45 lines
1.0 KiB
JavaScript
45 lines
1.0 KiB
JavaScript
import baseGetTag from './.internal/baseGetTag.js'
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import isObjectLike from './isObjectLike.js'
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/**
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* Checks if `value` is a plain object, that is, an object created by the
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* `Object` constructor or one with a `[[Prototype]]` of `null`.
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*
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* @since 0.8.0
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* @category Lang
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* @param {*} value The value to check.
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* @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
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* @example
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*
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* function Foo() {
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* this.a = 1
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* }
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*
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* isPlainObject(new Foo)
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* // => false
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*
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* isPlainObject([1, 2, 3])
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* // => false
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*
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* isPlainObject({ 'x': 0, 'y': 0 })
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* // => true
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*
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* isPlainObject(Object.create(null))
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* // => true
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*/
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function isPlainObject(value) {
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if (!isObjectLike(value) || baseGetTag(value) != '[object Object]') {
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return false
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}
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if (Object.getPrototypeOf(value) === null) {
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return true
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}
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let proto = value
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while (Object.getPrototypeOf(proto) !== null) {
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proto = Object.getPrototypeOf(proto)
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}
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return Object.getPrototypeOf(value) === proto
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}
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export default isPlainObject
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