Array flattening and de-weight

Array Flattening

//ES5 notationfunctionFlatten (arr) {returnarr.reduce (funcion (pre,cur,index) {returnPre.concat (Array.isarray (cur)?Flatten (cur): cur); },[]);}//ES6 notationfunctionFaltten (arr) {//arr can flatten an array, and if you have an inline array in an array, you need to loop through the flat     while(Arr.some (item =Array.isarray (item)) {arr=[].concat (... arr.); }    returnarr;}

array de-weight

// ES5 notation function Unique (arr) {    return arr.filter (function(item,index,arr) {        return arr.indexof (item) >= index;    }); // ES6 notation function Unique (arr) {    return [... New Set (arr)];}

Reference: HTTPS://JUEJIN.IM/POST/59716F15F265DA6C4C500FC7

Array flattening and de-weight