let arr22 = [1,2,[3,4],[5,6]]; console.log(Array.prototype.concat.apply([],arr22)) //[1,2,3,4,5,6]
1, first of all look at the apply () and concat () method
- Other objects .apply method name (the current object, [parameter 1, parameter 2, parameter 3]): the current object to use other objects, and pass parameters.
- concat (): Array stitching, returns a new array
2, the multi-dimensional array into a one-dimensional dimensionality reduction. First, the n-dimensional array dimensionality reduction is n-1 dimensional, sequentially and recursively, one-dimensional dimensionality reduction.
Recursive need to know (1) recursively conditions; (2) end conditions. Recursive function passing an array parameter is the time when the array element of the array, recursively; array element of the array is not the time, to push the new array element.
Analyzing a large array element is not a method of: Array.isArray (ele);
- Recursive conditions: when there is a time element of the array object array
- End condition: When there is no element of the array object array
let arr22 = [1,2,[3,4],[5,6]]; var newArr = []; var f22 = function(arr) { for(let i = 0;i < arr.length;i++){ if(Array.isArray(arr[i])){ f22(arr[i]); }else{ newArr.push(arr[i]); } } }; f22(arr22); console.log(newArr);