unshift () method to add one or more elements to the beginning of the array, and returns the new length.
shift () method is used to remove the first element of the array from which, and returns the value of the first element.
splice () method can remove zero or more elements from the beginning of the index, and to replace those removed element with one or more values of the parameters declared in the list.
One, two elements Commutator
function swapArr(arr, index1, index2) {
arr[index1] = arr.splice(index2, 1, arr[index1])[0];
return arr;
}
Second, the top mobile
function toFirst(fieldData,index) {
if(index!=0){
// fieldData[index] = fieldData.splice(0, 1, fieldData[index])[0]; 这种方法是与另一个元素交换了位子，
fieldData.unshift(fieldData.splice(index , 1)[0]);
}
Third, moving up on a grid
function upGo(fieldData,index){
if(index!=0){
fieldData[index] = fieldData.splice(index-1, 1, fieldData[index])[0];
}else{
fieldData.push(fieldData.shift());
}
}
Fourth, the move down one space
function downGo(fieldData,index) {
if(index!=fieldData.length-1){
fieldData[index] = fieldData.splice(index+1, 1, fieldData[index])[0];
}else{
fieldData.unshift( fieldData.splice(index,1)[0]);
}
}
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