52 lines
1.1 KiB
JavaScript
52 lines
1.1 KiB
JavaScript
// @flow
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module.exports = function shallowEqual<T, U>(
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objA?: ?T,
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objB?: ?U,
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compare?: ?(objValue: any, otherValue: any, key?: string) => boolean | void,
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compareContext?: ?any
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): boolean {
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var ret = compare ? compare.call(compareContext, objA, objB) : void 0;
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if (ret !== void 0) {
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return !!ret;
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}
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if (objA === objB) {
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return true;
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}
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if (typeof objA !== "object" || !objA || typeof objB !== "object" || !objB) {
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return false;
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}
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var keysA = Object.keys(objA);
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var keysB = Object.keys(objB);
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if (keysA.length !== keysB.length) {
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return false;
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}
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var bHasOwnProperty = Object.prototype.hasOwnProperty.bind(objB);
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// Test for A's keys different from B.
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for (var idx = 0; idx < keysA.length; idx++) {
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var key = keysA[idx];
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if (!bHasOwnProperty(key)) {
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return false;
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}
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var valueA = objA[key];
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var valueB = objB[key];
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ret = compare ? compare.call(compareContext, valueA, valueB, key) : void 0;
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if (ret === false || (ret === void 0 && valueA !== valueB)) {
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return false;
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}
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}
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return true;
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};
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