ht_hooks/lib/usePrevious/index.js

ht React 业务 Hooks

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = void 0;
var _react = require("react");
var defaultShouldUpdate = function defaultShouldUpdate(a, b) {
  return !Object.is(a, b);
}; //判断两值是否一致决定是否更新
function usePrevious(state, shouldUpdate) {
  if (shouldUpdate === void 0) {
    shouldUpdate = defaultShouldUpdate;
  }
  var prevRef = (0, _react.useRef)(); //初始prevRef.current=undefined
  var curRef = (0, _react.useRef)(); //初始curRef.current=undefined
  if (shouldUpdate(curRef.current, state)) {
    //初始初始curRef.current=undefined肯定不等于state，需要更新
    prevRef.current = curRef.current;
    curRef.current = state;
  }
  return prevRef.current;
}
var _default = exports["default"] = usePrevious;