86 lines
1.2 KiB
Markdown
86 lines
1.2 KiB
Markdown
# Presentation of the main ES6 features
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## Spread Operator
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It allows an iterable to expand items in it.
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```javascript
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array = [1, 2];
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appended = [3,4];
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all = [...aray, ...appended]
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console.log(all)
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```
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This can be usefull in some situations like this one :
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```javascript
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array = [1, 2, 3, 4];
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console.log(Math.min(...array));
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```
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instead of the old syntax
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```javascript
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array = [1, 2, 3, 4];
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console.log(Math.min.apply(null, array));
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```
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## Rest Operator
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Represent infinite number or args in an array
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```javascript
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const sum = (...numbers) => {
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return numbers.reduce((previous, current) => {
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return previous + current;
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});
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};
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```
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## Arrow Function
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Function can now be written like this
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```javascript
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const f = (a, b) => a + b;
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console.log(f(1,2));
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```
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instead of
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```javascript
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function f(a, b) {
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return a + b;
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}
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console.log(f(1,2));
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```
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## Default parameters
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With arrow syntax !
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```javascript
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const f = (a = 10) => console.log(a);
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f();
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f(1);
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```
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## Destructuring (arrays and objects)
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With arrays
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```javascript
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const array = [1, 2];
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const [a, b] = array;
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console.log(a, b)
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```
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or objects
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```javascript
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const person = { name: "Jesus", age: "33" };
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const { name, age } = person;
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console.log(name, age);
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```
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