algorithm: A JavaScript repository from locphan2207

Step to init a React app:

Use create-react-app: yarn create react-app <name>
Install prettier, eslint-plugin-prettier, stylelint, stylelint-prettier
Add eslint config to package.json:

"eslintConfig": {
    "extends": "react-app",
    "plugins": [
      "prettier"
    ],
    "rules": {
      "prettier/prettier": "error"
    },
    "settings": {
      "import/resolver": {
        "node": {
          "moduleDirectory": [
            "node_modules",
            "src/"
          ]
        }
      }
    }
  },

Create jsconfig.json with:

{
  "compilerOptions": {
    "baseUrl": "src"
  },
  "include": ["src"]
}

Create .stylelintrc with:

{
  "plugins": ["stylelint-prettier"],
  "rules": {
    "prettier/prettier": true
  }
}

Create .prettierrc with:

{
  "semi": false,
  "trailingComma": "es5"
}

Git init, create .gitignore for node_modules

ReSTful API:

API that use HTTP request to get, create, update, or delete data from server to client.

Closure

A function inside another function that can have access to variables declared from the outer functions
Closure can update the outer variables

Hoisting

Variables are in scope of the closest outer function, NOT in scope of the block.
Ex: If we declare a variable inside for loop, it is not in scope of that for only, it is still in scope the the function that contains the for loop.
Re-define the variable in different blocks inside the same function is the same as re-assigning same variable with new value in a function.

Class

Declare a class as a function with Capitalize name
To create instance variable, use this.<variable>
To create methods, use <Class>.prototype = function() {...} because when we put methods into prototype, it will be only create one instance of that method inside its prototype. Every instances of the class will look to that prototype to search for/use that method
static method is same as Class method, it can be called without the need of creating class instances
Ex:

  function Kitten(name, age) {
    this.name = name;
    this.age = age;
  }

  Kitten.prototype.meow = function () {
    console.log(this.name + ' says "meow!"');
  };

  k1 = new Kitten("Earl", 2);
  k2 = new Kitten("Houdini", 1);

Undefined vs null vs undecleared

Undecleared: Never decleare a name of a variable
Undefined: Just decleare a variable, but no assign it to a value or function
Null: variable with a value null means nothing in general.

Async and await

They are ES6 syntax that has the same meaning as .then for Promise object
Ex, we have this ES5 function:

function action() {
    fetch('https://...')
      .then(res => res.json())
      .then(json => console.log(json));
}

In ES6, we can use async/await syntax like so:

async function action() {
    const res = await fetch('https://...');
    const json = await res.json();
    console.log(json);
}

locphan2207/algorithm