数组操作.md

• 判断是否是数组

export const isArray = arr => return toString.call(arr) == '[object Array]';

• 基本类型数组去重

export const uniqueArr = arr => [...new Set(arr)];

• 数组并集

export const unionArr = (a, b) => [...new Set([...a, ...b])];

• 数组交集

export const intersectArr = (a, b) => [...new Set([...a].filter(x => b.has(x)))];

• 数组差集

export const differenceArr = (a, b) => [...new Set([...a].filter(x => !b.has(x)))];

• 对象数组单个键值匹配去重

export const uniqKeyInArr = (arr, key) => {
 let cache = {};
 return arr.reduceRight((item, next) => {
  cache[next[key]] ? '' : cache[next[key]] = true && item.push(next);
  return item;
 }, []);
}

• 对象数组完全匹配去重

export const uniqObjInArr = arr =>
    Array.from(new Set(arr.map(JSON.stringify))).map(JSON.parse);

• 规整多重数组

export const flatten = arr => {
 if (!Array.isArray(arr)) return arr;
 return arr.reduce((done, curr) => done.concat(flatten(curr)), [])
}