cookbook 之 utils

[imyangyong]

Input 或 TextArea 获取焦点时，将光标移至末尾
/**
   * method move cursor to end when focus. 
   * @param {Object} el target html dom.
   * @link https://davidwalsh.name/caret-end
   */
function moveCursorToEnd = el => {
    if (typeof el.selectionStart === 'number') {
      el.selectionStart = el.selectionEnd = el.value.length;
    } else if (typeof el.createTextRange !== 'undefined') {
      const range = el.createTextRange();
      range.collapse(false);
      range.select();
    }
  }
======
深拷贝（可用 lodash 的 _.cloneDeep 代替）
/**
   * method deep clone. 
   * @param {Object} source The object that will be cloned.
   */
function deepClone(source){
  if (!source) return source;
  if (source instanceof Date) return new Date(source);
  if (source instanceof RegExp) return new RegExp(source);
  if (typeof source !== 'object') return source;

  let newSource = new source.constructor();

  for(var key in source){
    newSource[key] = deepClone(source[key])
  }
  
  return newSource;
}
======
Object Keys 重命名
/**
   * method rename object keys. 
   * @param {Object} keysMap 新旧key对象形式的键值对.
   * @param {Object} obj 原始要改变的对象.
   */
const  renameKeys = (keysMap, obj) => Object
  .keys(obj)
  .reduce((acc, key) => ({
      ...acc,
      ...{ [keysMap[key] || key]: obj[key] }
  }), {});
// 应用示例：
keysMap = {
  name: 'firstName',
  job: 'passion'
};
obj = {
  name: 'YangYong',
  job: 'Front-End Master'
};
renameKeys(keysMap, obj);
// { firstName: 'YangYong', passion: 'Front-End Master' }
===