#react

deepEquals.js

function deepEquals(a, b, ca = [], cb = []) {
  // Partially extracted from node-deeper and adapted to exclude comparison
  // checks for functions.
  // https://github.com/othiym23/node-deeper
  if (a === b) {
    return true;
  } else if (typeof a === "function" || typeof b === "function") {
    // Assume all functions are equivalent
    // see https://github.com/mozilla-services/react-jsonschema-form/issues/255
    return true;
  } else if (typeof a !== "object" || typeof b !== "object") {
    return false;
  } else if (a === null || b === null) {
    return false;
  } else if (a instanceof Date && b instanceof Date) {
    return a.getTime() === b.getTime();
  } else if (a instanceof RegExp && b instanceof RegExp) {
    return (
      a.source === b.source &&
      a.global === b.global &&
      a.multiline === b.multiline &&
      a.lastIndex === b.lastIndex &&
      a.ignoreCase === b.ignoreCase
    );
  } else if (isArguments(a) || isArguments(b)) {
    if (!(isArguments(a) && isArguments(b))) {
      return false;
    }
    let slice = Array.prototype.slice;
    return deepEquals(slice.call(a), slice.call(b), ca, cb);
  } else {
    if (a.constructor !== b.constructor) {
      return false;
    }

    let ka = Object.keys(a);
    let kb = Object.keys(b);
    // don't bother with stack acrobatics if there's nothing there
    if (ka.length === 0 && kb.length === 0) {
      return true;
    }
    if (ka.length !== kb.length) {
      return false;
    }

    let cal = ca.length;
    while (cal--) {
      if (ca[cal] === a) {
        return cb[cal] === b;
      }
    }
    ca.push(a);
    cb.push(b);

    ka.sort();
    kb.sort();
    for (var j = ka.length - 1; j >= 0; j--) {
      if (ka[j] !== kb[j]) {
        return false;
      }
    }

    let key;
    for (let k = ka.length - 1; k >= 0; k--) {
      key = ka[k];
      if (!deepEquals(a[key], b[key], ca, cb)) {
        return false;
      }
    }

    ca.pop();
    cb.pop();

    return true;
  }
}

shouldRender.js

export function shouldRender(comp, nextProps, nextState) {
  const { props, state } = comp;
  return !deepEquals(props, nextProps) || !deepEquals(state, nextState);
}