通过Object.is判断之前依赖的各项是否与之后的依赖完全相等

源码

packages/shared/objectIs.js

function is(x: any, y: any) {
  return (
    (x === y && (x !== 0 || 1 / x === 1 / y)) || (x !== x && y !== y) // eslint-disable-line no-self-compare
  );
}

const objectIs: (x: any, y: any) => boolean =
  typeof Object.is === 'function' ? Object.is : is;

export default objectIs;

packages/react-reconciler/src/ReactFiberHooks.new.js

function areHookInputsEqual(
  nextDeps: Array<mixed>,
  prevDeps: Array<mixed> | null,
) {

  if (prevDeps === null) {
    return false;
  }

  for (let i = 0; i < prevDeps.length && i < nextDeps.length; i++) {
    if (is(nextDeps[i], prevDeps[i])) {
      continue;
    }
    return false;
  }
  return true;
}