JavaScript syntax: Difference between revisions

Revision as of 21:34, 22 January 2021

Revision as of 21:47, 22 January 2021

Line 740:

// x, y is the argument. 'return x + y' is the function body, which is the last in the argument list.

var add = new Function('x', 'y', 'return x + y');

var t = add(1, 2); // => 3

console.log(t); // 3

</syntaxhighlight>

Line 750 ⟶ 749:

return x + y;

};

var t = add(1, 2); // => 3

console.log(t); // 3

</syntaxhighlight>

In ES6, arrow function syntax was added, allowing functions that return a value to be more concise. They also retain the <tt>this</tt> of the global object instead of inheriting it from where it was called / what it was called on, unlike the <tt>function() {}</tt> expression.

There exists a shorthand for assigning a function expression to a variable, and is as follows:

<syntaxhighlight lang="javascript">

var add = ((x, y) => {return x + y);};

// values can also be implicitly returned (i.e. no return statement is needed)

var addImplicit = (x, y) => x + y;

add(1, 2); // => 3

addImplicit(1, 2) // => 3

</syntaxhighlight>

For functions that need to be hoisted, there is a separate expression:

<syntaxhighlight lang="javascript">

Line 760 ⟶ 769:

return x + y;

}

var t = add(1, 2); // => 3

console.log(t); // 3

</syntaxhighlight>

Hoisting allows you to use the function before it is "declared":

Or

<syntaxhighlight lang="javascript">

var add = ((x1, y2); // => {3, not a ReferenceError

function add(x, y) {

return x + y;

});

// or

var add = ((x, y) => x + y);

var t = add(1, 2);

console.log(t); // 3

</syntaxhighlight>

A function instance has properties and methods.

Line 782 ⟶ 788:

}

console.log(subtract.length); // => 2, expectedarity of the function amount(number of arguments.)

console.log(subtract.toString());

Line 791 ⟶ 797:

*/

</syntaxhighlight>

New functions can be

==Operators==