WebPACK
1. Installation NodeJS
2. Installation npm install -g webpack
bugs:
NPM given installation package rollbackFailedOptiona L
https://blog.csdn.net/qq_34351732/article/details/78705997
NPM config RM Proxy
NPM-config RM HTTPS Proxy
then npm install -g cnpm -registry = https use: //registry.npm.taobao.org installation Taobao the CNPM
Css-Loader:
JS form of
command-line form
- watch real-time updates --progress progress --display-moudles display module displays --display-reason reasons
Webpack.config.js configuration:
You can configure webpack command package.json
then npm WebPACK RUN
the entry inlet:
array
entry: [./ js / index1.js, / js / index2.js.]
Object
the entry: {
the Package1: './ JS / The index.js',}
the Output:
Babel-Loader: installation
Npm Babel-dev---save the install Babel Loader Core-
NPM the install @ Babel / Core --save
NPM @ Babel the install / dev-PRESET---save the env
Use:
Babel RESET - package.json
Bug:
ES6
19/3/4
variables:
ES5: var (global scope)
ES6:
the let (equivalent var) to act only on block-level scope, not a pre-parsing.
const (constant defined) Object.freeze (object).
Config = {const
the Host:
Test
}
Destructuring assignment:
the let A =. 1, B = 2, C =. 3;
Let [A, B, C] = [l, 2,3];
console.log (A, B, C);
Left and right sides, the structure to be consistent,
Let [A, [B, C]] = [. 1, [2,3]];
Let = {JSON name: Test, Age: 13 is, Sex: MALE};
Let {A: a1, b: b1, c: c1} = json;
give default values:
Let {A, B, C = 'C'} = { 'A', 'B'};
exchange assignment :
the let A = 12 is;
Let 2 = B;
Let [A, B] = [B, A];
String template :
Let name = 'A';
Let Sex = 'b';
Let str = "This person is called
{sex} ";
Srt.includes () Return value: to true / to false
Navigator.userAgent.includes ( 'Chrome') Analyzing browser
str.endwidth ()
Str.startwidth ()
Str.repeat (number);
Function default parameters
Function Show ({X = 0, Y = 0} = {}) {
}
the Show ();
function default parameters have been defined and can not be redefined
extended operator, reset operator
...
Let ARR = [A, B , c];
console.log (... arr); array expansion
Let a =Array.prototype.slice.call(arguments); 排序
a.sort();
Arrow function
() => things return
() => {
statement
the Return
}
the this problem, where the object definition function, is not where the runtime objects
arrow there is no function arguments
6. array lively circulation
Arr.foreach (
Function (Val, index, ARR) {}
)
Arr.map ((Val, index, ARR) => (
console.log (Val, index.arr);
));
very Useful, mapping, we need to meet return, return a new array
Arr.filter ();
Arr.some (); look for similar returns in line with an element to true
Arr.every ();
Array.of ( 'abc', 'bcd ', 'cde') to a set of values converted into an array
Array.from ()
Arr.find () Returns not found undefine
Arr.findindex () not found returns -1
Arr.fill ( 'filled stuff', start position, end position);
Object
Object.is ( 'NaN3', 'NaN3') determines whether the two objects are equal
Let JS = {A:}. 1;
Let JS2 = {B:. 1, A: 2};
Let JS3 = {C:. 1};
Object.assign ({}, JSON, json2, json3) 1. 2. copy an object to merge objects
For(let key of object.keys(js2)){
Console.log(key);
}
Let item of entries(json)
9.Promise
role: to solve the problem of asynchronous callback
Let Promise Promise new new = (function (Resolve, Reject) {
the If (A == 10) {
Resolve ( 'success');
} {the else
Reject ( 'failed');
}
});
Promise.then(res=>{
Console.log(res);
},error=>{
Console.log(err);
}).catch(){};
Promise.resolve ( "aaa"); the thing is converted into a state promise resolve objects
Promise.reject ( "BB");
. Promise.all ([P1, P2, P3]) the then (RES => {}) three a must for a successful state
Promise.race ([p1, p2, p3 ]) on the line as long as a success
Modular
the Export const = A. 1;
the Export const B = 2;
the Export const. 3 = C;
The Export {
A AS A, AS B BA,} Syntax two
Export default
{A Import, B, C} from './moudles/1.js';
. 1 written at any position, automatically elevating tip
2 to export content module, the timer if there are changes, modifications will be outside
3import only introduced once.
4. if statement is not written in the
Import * as modto from './moudles/1.js'
dynamic introduction, the object is similar to promise NodeJS:
Import ( 'JS files') .then (res => { })
class and Inherited
Const Person = {class
the Constructor () {
}
AAA { method name can be a variable
}
}
Static method
Class Person {
the Static Show () {
}}
Person.show (); can be called directly
Inherited
Super (arug); properties inherited from the parent class
. Super method name (); inherited methods of the parent class
Generator & 12.symbol
Generator function
solve asynchronous, the async problem deeply nested ()
Syntax:
Function * Gen () {
Yield 'available for purchase';
Yield 'to';
the Return 'Test';
}
Let G1 = Gen ();
console.log ( g1.next () ); // {value: 'available for purchase', DONE: to false}
traverse
the For (Val of the let G1) {
console.log (Val);}
deconstruction:
Let [A, B] = Gen ();
... Gen ();
file system write
promise embodiment
Generator mode
async mode
1await promise can be followed by an object, or may be numbers, characters,
2Async promise is the function returns the object
3 as long as the state is a reject, the rear interrupt execution (try {} catch {} solution)
13.set data structure
Let setarr = new set ( ' 1 ',' 3 ',' 4 '); array-like, but can not repeat value
Set.add () Add
Set.delete remove
Set.has () has a value
Set.size ()
Set.clear ()
new weakset ({}) stores data json
Map
Map.set (Key, value) may be any type Key
Map.get (Key)
Map.delete ()
Map.has ()
Map.clear ()
Weakmap key can only be subject
16. A number of changes and new math something
binary:
the let A = 0b101010
octal
Let a = 0o666
Number.isfinite (a) is determined is not a number
Number.isnan ()
Number.isinteger () judgment is not an integer
safe Integer:
- (2 ^ 53) -1 ^ 53-1 to 2
Number.isSafeinteger ()
Math.trunc (4.55) retention integer
Math.sign () determines whether a positive number, n is 1, -1, 0, is negative 0
Math.cbrt () calculates the cube root of a number
Taking date
named capture
/ (\ d?) - / ({2}?)
