src/shallowEqual.js
export default function shallowEqual(objA, objB) {
if (objA === objB) {
return true
}
const keysA = Object.keys(objA)
const keysB = Object.keys(objB)
if (keysA.length !== keysB.length) {
return false
}
// Test for A's keys different from B.
const hasOwn = Object.prototype.hasOwnProperty
for (let i = 0; i < keysA.length; i++) {
if (!hasOwn.call(objB, keysA[i]) ||
objA[keysA[i]] !== objB[keysA[i]]) {
return false
}
}
return true
}