src/util/shallowEqual.js
const hasOwnProperty = Object.prototype.hasOwnProperty;
function is(x, y) {
if (x === y) {
return x !== 0 || y !== 0 || 1 / x === 1 / y;
}
return x !== x && y !== y;
}
export default function shallowEqual(objA, objB) {
if (is(objA, objB)) {
return true;
}
if (typeof objA !== 'object' || objA === null ||
typeof objB !== 'object' || objB === null) {
return false;
}
const keysA = Object.keys(objA);
const keysB = Object.keys(objB);
if (keysA.length !== keysB.length) {
return false;
}
for (let i=0; i<keysA.length; i++) {
if (!hasOwnProperty.call(objB, keysA[i]) ||
!is(objA[keysA[i]], objB[keysA[i]])) {
return false;
}
}
return true;
}