React Memo的最小实现

smiple_memo.ts

const memo = (component, comparision) => {
  let prevProps = {};
  let nextProps = {};
  let memoResult = null;
  let initialized = false;
  
  const comparisionFn = comparision ? comparision : (nextProps, prevProps) => {
    return nextProps === prevProps;
  }
  
  return (props) => {
    prevProps = nextProps;
    nextProps = props;
    
    
    if (comparisionFn(nextProps, prevProps) && initialized) {
      console.log('memorized');
      return memoResult;
    } else {
      console.log('not memorized');
      memoResult = component(props);
      initialized = true;
      return memoResult;
    }
    
  };
}

const comp = (props) => {
  return props;
}

const memoComp = memo(comp);

const props1 = {'a': 'hello'}

console.log(memoComp(props1))
console.log(memoComp(props1))
console.log(memoComp({'a': 'aaa'}))