just-safe-set/index.mjs

set value at property, create intermediate properties if necessary

var objectSafeSet = set;

/*
  var obj1 = {};
  set(obj1, 'a.aa.aaa', 4); // true
  obj1; // {a: {aa: {aaa: 4}}}

  var obj2 = {};
  set(obj2, ['a', 'aa', 'aaa'], 4); // true
  obj2; // {a: {aa: {aaa: 4}}}

  var obj3 = {a: {aa: {aaa: 2}}};
  set(obj3, 'a.aa.aaa', 3); // true
  obj3; // {a: {aa: {aaa: 3}}}

  const obj5 = {a: {}};
  const sym = Symbol();
  set(obj5.a, sym, 7); // true
  obj5; // {a: {Symbol(): 7}}
*/

function set(obj, propsArg, value) {
  var props, lastProp;
  if (Array.isArray(propsArg)) {
    props = propsArg.slice(0);
  }
  if (typeof propsArg == 'string') {
    props = propsArg.split('.');
  }
  if (typeof propsArg == 'symbol') {
    props = [propsArg];
  }
  if (!Array.isArray(props)) {
    throw new Error('props arg must be an array, a string or a symbol');
  }
  lastProp = props.pop();
  if (!lastProp) {
    return false;
  }
  prototypeCheck(lastProp);
  var thisProp;
  while ((thisProp = props.shift())) {
    prototypeCheck(thisProp);
    if (typeof obj[thisProp] == 'undefined') {
      obj[thisProp] = {};
    }
    obj = obj[thisProp];
    if (!obj || typeof obj != 'object') {
      return false;
    }
  }
  obj[lastProp] = value;
  return true;
}

function prototypeCheck(prop) {
  // coercion is intentional to catch prop values like `['__proto__']`
  if (prop == '__proto__' || prop == 'constructor' || prop == 'prototype') {
    throw new Error('setting of prototype values not supported');
  }
}

export {objectSafeSet as default};