Summary of JS array emptying (delete) method

Emptying the array is a common JavaScript job, but I often see it in the wrong way. Many times, developers will create a new array, such as the following:

Assignment to []

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MyArray = []; Bad way. var ary = [1,2,3,4]; ary = []; Assignment to an empty array to empty the original array

To create an empty array to empty it is obviously not the best way to set the length property of the array to 0:

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myarray.length = 0; good!

Set length to zero empty the current array instead of creating another empty array! This can help you avoid pointer problems with arrays. If you use the previous method:

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A = [1,2,3,4,5] B = A A = [] Console.log (B)//[1,2,3,4,5], the original array is still not empty, a just points to the new empty array

Set a length of 0 so that both A and B can be emptied.

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var a = []; for (var i=0; i< 1000000; i++) { A.push (i); } var start = new Date (); a = []; a.length = 0; var end = new Date (); alert (End-start);

Other attributes of the array are preserved, and mode 3 is not retained. A lot of people think that Mode 2 is more efficient because it only assigns length to the value, and mode 3 builds the object again. The test is precisely the way 3 efficiency is high.