If you use a this inside an arrow function, it behaves exactly as any other variable reference, which is that the scope chain is consulted to find a function scope (non-arrow function) where it is defined, and to use that one. 翻译:如果在箭头函数中使用this,则它的行为与任何其他变量引用...
Prefixer.prototype.prefixArray=function(arr) {returnarr.map(function(x) {returnthis.prefix +x; },this);//(A)}; 方案3 绑定this 你可以使用bind()方法来告诉函数是谁调用的 functionPrefixer(prefix) {this.prefix =prefix; } Prefixer.prototype.prefixArray=function(arr) {returnarr.map(function(x) ...
Difference of function expressions and function declarations Arrow function do save us a few lines of code and characters ,but the real purpose of the arrow funcion is to handlethethiskeyword within functions. this behaves differently inside an arrow function. Let's take a look at how the this...
Here, theinnerFunc()function is an arrow function. And inside the arrow function,thisrefers to the parent's scope, i.e., the scope of thePerson()function. Hence,this.agegives25. this Keyword Inside a Regular Function As stated above,this keywordrefers to the function where it is called....
Let's say we replace our anonymous function inside our setInterval with an arrow function:let counter2 = { initial: 100, interval: 1000, startCounting: function () { setInterval(() => { this.initial++; console.log(this.initial); // works }, this.interval); } } counter2.start...
(function () { // open IIFE // inside IIFE })(); // close IIFE You can save a few characters if you use an Immediately Invoked Arrow Function (IIAF):(() => { return 123 })(); 13.6.1 Semicolons Similarly to IIFEs, you should terminate IIAFs with semicolons (or use an ...
var func = () => { foo: function() {} }; // SyntaxError: function statement requires a name This is because the code inside braces ({}) is parsed as a sequence of statements (i.e. foo is treated like a label, not a key in an object literal). Remember to wrap the object ...
It’s important to remember that you can’t change the value ofthisinside an arrow function. If you need thethiskeyword to refer to the object that called the function, then you need to use the oldfunctionkeyword. Arrow function doesn’t have arguments binding ...
Example: Arrow function with default parametersIn the below example, we passed the default value of the parameters to the arrow function. When you will not pass the corresponding argument values, these default values will be used inside the function body. ...
The arrow function inside the.map()function develops over a series of statements, at the end of which it returns an object. This makes using curly braces around the body of the function unavoidable. Also, as you’re using curly braces, an implicit return is not an option. You must use ...