heIIfire

const a1 = [ 1, 5, 8, 7], a2 = [];

a2[0] = a1[0];
a2[2] = a1[1];
a2[3] = a1[2];
a2[1] = a1[3];

console.log(a2); // [1, 7, 5, 8]

The key that identifies the JS script file. If null, it will use $url as the key. If two JS files are registered with the same key at the same position, the latter will overwrite the former. Note that position option takes precedence, thus files registered with the same key, but different position option will not override each other.

.
├── index.js
├── package.json
└── sub
    ├── a.js
    └── b.js

console.log('module a');
  module.exports = module;

const moduleA = require('./sub/a.js');
moduleA.require('./b.js');
require('./b.js');

$ node index.js
module a
module b
module.js:515
    throw err;
    ^

Error: Cannot find module './b.js'
    at Function.Module._resolveFilename (module.js:513:15)
    at Function.Module._load (module.js:463:25)
    at Module.require (module.js:556:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/home/anton/projects/node/require-test/index.js:3:1)
    at Module._compile (module.js:612:30)
    at Object.Module._extensions..js (module.js:623:10)
    at Module.load (module.js:531:32)
    at tryModuleLoad (module.js:494:12)
    at Function.Module._load (module.js:486:3)

import First from "./first"
import Second from "./second"
class A extends Component {
render(){
return(
// как здесь возвращать несколько компонентов? типо 
<div>
<First>
<Second>
</div
);
}
}

loaders: [
          {
              test: /\.js$/,
              loader: 'babel-loader',
              exclude: [/node_modules/],
              query: {
                  presets: ['es2015', 'react']
              }
          }
]

$sql = "INSERT INTO catalog (title, author, pubyear,price) VALUES ('" . $title . "','" . $author . "','" . $pubyear . "','" . $price . "')";

$sql = "INSERT INTO catalog (title, author, pubyear,price) VALUES (?,?,?,?)";

Returns a string of up to length - 1 bytes read from the file pointed