javascript - 如何从数组中删除重复值？当数组中的对象属性未定义时，我的代码失败

Question

我期待一个通用的解决方案，包括高阶对象作为数组的一个元素。

const input1 = [1,2,4,6,'4','1',{a:1},{a:1}]; //my code works
const input2 = [1,2,4,6,'4','1',{a:undefined},{b:undefined}]; //my code fails.
    
function deDuplicate(arr) {
  let obj = {};
  arr.forEach(value => {
    if (!obj[JSON.stringify(value) + typeof value]) obj[JSON.stringify(value) + typeof value] = value;
  });
  return Object.values(obj);
}

console.log(deDuplicate(input2));

Answer 1

包括lodash https://cdnjs.com/libraries/lodash.js或 https://www.jsdelivr.com/package/npm/lodash

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

    const input1 = [1,2,4,6,'4','1',{a:1},{a:1}]; //my code works
    const input2 = [1,2,4,6,'4','1',{a:undefined},{b:undefined}]; //my code fails.

    function deDuplicate(arr) {
        let res = []
        for(const el of arr) {
            const dublicateIndex = res.findIndex( (el2) => {

                // if both nulls
                if( _.isNull(el) && _.isNull(el2) ) {
                    return true
                }

                // if both undefined
                if( _.isUndefined(el) && _.isUndefined(el2) ) {
                    return true
                }


                // check both are string, or numbers
                if(
                    ( _.isNumber(el) || _.isString(el)) &&
                    ( _.isNumber(el2) || _.isString(el2) )
                ) {

                    return el.toString() === el2.toString()
                }

                // check if one is object, other not
                if(_.isObject(el) !== _.isObject(el2)) {
                    return false
                }

                // check both is object
                if(_.isObject(el) === _.isObject(el2)) {
                    return _.isEqual(el, el2)
                }

                return _.isEqual(el, el2)
            })

            if(dublicateIndex === -1) {
                res.push(el)
            }
        }
        return res
    }

    console.log(deDuplicate(input3));

输入 1 - [ 1, 2, 4, 6, { a: 1 } ]

input2 - [ 1, 2, 4, 6, {a: undefined }, { b: undefined } ]

实例https://jsfiddle.net/9cx4kget/