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This article mainly introduces "what is the meaning of the three dots in JavaScript". In the daily operation, I believe that many people have doubts about the meaning of the three dots in JavaScript. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts of "what is the meaning of the three dots in JavaScript?" Next, please follow the editor to study!

The operating environment of this tutorial: windows7 system, ECMAScript version 6, Dell G3 computer.

In JavaScript, three dots (...) are really called extension operators, which are new additions to ES6. They can expand array expressions or string at the syntax level when function calls / array constructions are made, and object expressions can be expanded as key-value when constructing literal objects.

The literal quantity generally refers to the concise construction of [1 name:'chuichui' 2] or {3}, and the multi-layer nested array and three points of objects are powerless.

To put it bluntly, it means to take off your clothes, whether it's curly braces ([]) or curly braces ({}). Take them all off!

/ / Array var number = [1 name:'chuichui',height:176 2 console.log 3 4 5 5 var number 6] console.log (... console.log) / / 1 2 3 4 56 man / object var man = {name:'chuichui',height:176} console.log ({... man}) / {name:'chuichui',height:176}?

It has a wide range of uses, which we can see everywhere. Here are a few common examples.

Copy replication with it / / array var arr1 = ['hello'] var arr2 = [... arr1] arr2 / / [' hello'] / / object replication var obj1 = {name:'chuichui'} var obj2 = {... arr} ob12 / / {name:'chuichui'} merge it / / array var arr1 = ['hello'] var arr2 = [' chuichui'] var mergeArr = [. Arr1,...arr2] mergeArr / / ['hello'] 'chuichui'] / / object splitting and merging var obj1 = {name:'chuichui'} var obj2 = {height:176} var mergeObj = {... obj1,...obj2} mergeObj / / {name: "chuichui", height:176} character transfer array var arr1 = [.' hello'] arr1 / / ["h", "e", "l", "l", "o"] function passes parameters to it

Can be combined with normal functions, flexible use

Function f (vMagnewPercience x repense yremenz) {} var args = [2mage3] f (1pr.. argspr 4rec. [5])

When we want to iterate the elements in the array into function parameters, use it!

Function f (xjingyjinz) {} var args = [1 args 3] f (. Args) / / the previous method f.apply (null,args); at this point, the study of "what are the three dots in JavaScript" is over, hoping to solve everyone's doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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