AugurProject/augur-ui

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src/utils/should-component-update-pure.js

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export default function(nextProps, nextState) {
  return (
    isShallowUnEqual(nextProps, this.props) ||
    isShallowUnEqual(nextState, this.state)
  );
}

export function shouldComponentUpdateLog(nextProps, nextState) {
  return (
    isShallowUnEqual(nextProps, this.props, true) ||
    isShallowUnEqual(nextState, this.state, true)
  );
}

export function shouldComponentUpdateOnStateChangeOnly(nextProps, nextState) {
  return isShallowUnEqual(nextState, this.state);
}

function isShallowUnEqual(obj1, obj2, log) {
  // both arguments reference the same object
  if (obj1 === obj2) {
    return false;
  }

  // arguments are either not objects or undefined/null
  if (
    typeof obj1 !== "object" ||
    obj1 == null ||
    typeof obj2 !== "object" ||
    obj2 == null
  ) {
    return true;
  }

  const keysA = Object.keys(obj1);
  const keysB = Object.keys(obj2);
  const keysALen = keysA.length;

  // keys don't match
  if (keysALen !== keysB.length) {
    return true;
  }

  for (let i = 0; i < keysALen; i++) {
    // actual values are different + not functions
    if (
      obj1[keysA[i]] !== obj2[keysA[i]] &&
      typeof obj1[keysA[i]] !== "function"
    ) {
      log && console.log("------->", keysA[i], obj1[keysA[i]], obj2[keysA[i]]);
      return true;
    }
  }

  // nothing needs to be updated
  return false;
}