DEV Community: Falah Al Fitri

Axios return async await

Falah Al Fitri — Sun, 27 Aug 2023 10:50:44 +0000

Installing

Package manager
Using npm:

$ npm install axios

Once the package is installed, you can import the library using import or require approach:

const axios = require( 'axios' )

import axios from 'axios'

then, create return function

async function myPromise() {

    // return axios( 'https://example.com' )
    return await axios( 'https://example.com' )
        .then( function ( response ) {

            // Process html...
            return ( response )

        } )
        .catch( function ( err ) {

            // Crawling failed...
            return ( err )

        } );

}

And, call the function

(async () => {

    try {

        console.log( await myPromise() )

    } catch ( error ) {

        console.error( `Something went wrong. ${error.message}` );

    }

})();

All Code

/*
    https://www.npmjs.com/package/axios
    https://github.com/axios/axios
    https://axios-http.com/
 */

const axios = require('axios');

async function myPromise() {

    // return axios( 'https://example.com' )
    return await axios( 'https://example.com' )
        .then( function ( response ) {

            // Process html...
            return ( response )

        } )
        .catch( function ( err ) {

            // Crawling failed...
            return ( err )

        } );

}

/* --- */

(async () => {

    try {

        console.log( await myPromise() )

    } catch ( error ) {

        console.error( `Something went wrong. ${error.message}` );

    }

})();

repl.it

Thank you

NodeJS request

Falah Al Fitri — Wed, 07 Dec 2022 05:42:21 +0000

Request - Simplified HTTP client

Request is designed to be the simplest way possible to make http calls. It supports HTTPS and follows redirects by default.

request

// https://www.npmjs.com/package/request
const request = require('request')

/* --- */

request( 'https://example.com', function ( error, response, body ) {

    /*
        Print the error if one occurred
    */
    console.error( `error: ${error}` )

    /*
        Print the response status code if a response was received
    */
    console.log( 'statusCode:', response && response.statusCode)

    /*
        Print the HTML for the example homepage
    */
    console.log( `body: ${body}` )

} )

Example request

Example request callback

Example request promise

Example request promise return

Example request async/await

Javascript: Async/Await

Falah Al Fitri — Sun, 04 Dec 2022 08:07:08 +0000

"async and await make promises easier to write"

async makes a function return a Promise

await makes a function wait for a Promise

Async Syntax

The keyword async before a function makes the function return a promise:

async function myFunction() {

    // "Producing Code" (May take some time)

    return "Hello World"

}

Here is how to use the Promise:

// "Consuming Code" (Must wait for a fulfilled Promise)
myFunction().then(

    function( success ) { 

        /* code if successful */ 
        console.log( success )

    },

    function( error ) { 

        /* code if some error */ 
        console.error( error )

    }

)

Example

1 2 Display

Await Syntax

The await keyword can only be used inside an async function.

The await keyword makes the function pause the execution and wait for a resolved promise before it continues:

let value = await promise

Example

1 2 Display

3 Waiting for a file

4 Waiting for a file - return

Async Function (developer.mozilla.org)

The async function declaration declares an async function where the await keyword is permitted within the function body. The async and await keywords enable asynchronous, promise-based behavior to be written in a cleaner style, avoiding the need to explicitly configure promise chains.

...

JavaScript: Promise

Falah Al Fitri — Fri, 02 Dec 2022 01:31:35 +0000

"I Promise a Result!"

"Producing code" is code that can take some time

"Consuming code" is code that must wait for the result

A Promise is a JavaScript object that links producing code and consuming code

Promise Syntax

// "Producing Code" (May take some time)
let myPromise = new Promise( function( resolve, reject ) {  

    resolve() // when successful

    reject()  // when error

} )

// "Consuming Code" (Must wait for a fulfilled Promise)
myPromise.then(

    function( success ) { /* code if successful */ },

    function( error ) { /* code if some error */ }

)

Promise Object Properties

A JavaScript Promise object can be:

Pending
Fulfilled
Rejected

The Promise object supports two properties: state and result.

While a Promise object is "pending" (working), the result is undefined.

When a Promise object is "fulfilled", the result is a value.

When a Promise object is "rejected", the result is an error object.

Example promise

/*
    https://www.w3schools.com/js/js_promise.asp
 */

/* 
    "Producing Code" (May take some time) 
 */

let myPromise = new Promise( function ( resolve, reject ) {

    let x = 0   

    if ( x == 0 ) {

        /* when successful */
        resolve( 'OK' ) 

    } else {

        /* when error */
        reject( 'Error' )

    }

} )

/* --- */

/* 
    "Consuming Code" (Must wait for a fulfilled Promise) 
 */

myPromise.then(

    function ( success ) { 

        /* code if successful */ 
        console.log( success )

    },

    function ( error ) { 

        /* code if some error */ 
        console.error( error )

    }

)

Example promise return

/*
    https://www.w3schools.com/js/js_promise.asp
 */

/* 
    "Producing Code" (May take some time) 
 */

function myPromise() {

    return new Promise( function ( resolve, reject ) {

        let x = 0   

        if ( x == 0 ) {

            /* when successful */
            resolve( 'OK' ) 

        } else {

            /* when error */
            reject( 'Error' )

        }

    } )

}

/* --- */

/* 
    "Consuming Code" (Must wait for a fulfilled Promise) 
 */

myPromise().then(

    function ( success ) { 

        /* code if successful */ 
        console.log( success )

    },

    function ( error ) { 

        /* code if some error */ 
        console.error( error )

    }

)

Example promise return resolve

/*
    https://www.w3schools.com/js/js_promise.asp
 */

/* 
    "Producing Code" (May take some time) 
 */

function myPromise() {

    let result
    let x = 0   

    if ( x == 0 ) {

        /* when successful */
        result = 'OK'

    } else {

        /* when error */
        result = 'Error'

    }

    /* --- */

    return Promise.resolve( result )

}

/* --- */

/* 
    "Consuming Code" (Must wait for a fulfilled Promise) 
 */

myPromise().then(

    function ( success ) { 

        /* code if successful */ 
        console.log( success )

    },

    function ( error ) { 

        /* code if some error */ 
        console.error( error )

    }

)

Waiting for a Timeout

Waiting for a file

Promise (developer.mozilla.org)

The Promise object represents the eventual completion (or failure) of an asynchronous operation and its resulting value...

JavaScript: Asynchronous

Falah Al Fitri — Thu, 01 Dec 2022 02:02:39 +0000

"I will finish later!"

Asynchronous is functions running in parallel with other functions

In the real world, callbacks are most often used with asynchronous functions.

function myFunction( text, callback ) {

    console.log( text )

    /* --- */

    /* 
        call callback function
    */
    callback( 'text from myDisplayer (as callback function)' )  

}

function myDisplayer( text ) {

    console.log( text ) 

}

/*
    call myFunction
    myDisplayer passed into myFunction as an argument function
*/
myFunction( 'text from myFunction', myDisplayer )

/* --- */

// text from myFunction
// text from myDisplayer (as callback function)

Example

Note

When you pass a function as an argument, remember not to use parenthesis.

Right: myFunction( 'text from myFunction', myDisplayer )

Wrong: ~~myFunction( 'text from myFunction', myDisplayer() )~~

Waiting for a Timeout

Waiting for Intervals

Waiting for a file

Javascript: Callback

Falah Al Fitri — Thu, 01 Dec 2022 00:53:13 +0000

"I will call back later!"

Callback is a function passed as an argument to another function

This technique allows a function to call another function. A callback function can run after another function has finished

function myFunction( text, callback ) {

    console.log( text )

    /* --- */

    /* 
        call callback function
    */
    callback( 'text from myDisplayer (as callback function)' )  

}

function myDisplayer( text ) {

    console.log( text ) 

}

/*
    call myFunction
    myDisplayer passed into myFunction as an argument function
*/
myFunction( 'text from myFunction', myDisplayer )

/* --- */

// text from myFunction
// text from myDisplayer (as callback function)

Example

Note

When you pass a function as an argument, remember not to use parenthesis.

Right: myFunction( 'text from myFunction', myDisplayer )

Wrong: ~~myFunction( 'text from myFunction', myDisplayer() )~~

Waiting for a file

JavaScript Sorting Arrays

Falah Al Fitri — Thu, 23 Dec 2021 02:18:11 +0000

Array

The sort() method sorts an array alphabetically:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.sort(); // Apple,Banana,Mango,Orange

The reverse() method reverses the elements in an array.
You can use it to sort an array in descending order:

Example

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.reverse(); // Orange,Mango,Banana,Apple

Numeric Sort

By default, the sort() function sorts values as strings.

This works well for strings ("Apple" comes before "Banana").

However, if numbers are sorted as strings, "25" is bigger than "100", because "2" is bigger than "1".

Because of this, the sort() method will produce incorrect result when sorting numbers.

You can fix this by providing a compare function:

Example

const points = [40, 100, 1, 5, 25, 10];
points.sort( (a, b) => (a - b) ); // 1,5,10,25,40,100

Use the same trick to sort an array descending:

Example

const points = [40, 100, 1, 5, 25, 10];
points.sort( (a, b) => (b - a) ); // 100,40,25,10,5,1

Ref

HTML Table rowspan colspan

Falah Al Fitri — Mon, 20 Dec 2021 03:50:44 +0000

Cell that spans two rows

To make a cell span more than one row, use the rowspan attribute.

Cell that spans two columns

To make a cell span more than one column, use the colspan attribute.

        <table style="width:100%">

            <tr>
                <th rowspan="2">No</th>
                <th colspan="2">Driver</th>
                <th colspan="2">Team</th>
            </tr>

            <tr>
                <th>Image</th>
                <th>Name</th>
                <th>Logo</th>
                <th>Name</th>
            </tr>

            <tr>
                <td>1</td>
                <td>img1</td>
                <td>name1</td>
                <td>logo1</td>
                <td>name1</td>    
            </tr>

            <tr>
                <td>2</td>
                <td>img2</td>
                <td>name2</td>
                <td>img2</td>
                <td>name2</td>
            </tr>

        </table>

Embed replt

API newsapi.org | Express | for beginner

Falah Al Fitri — Tue, 07 Dec 2021 05:32:48 +0000

package.json

{
...
  "dependencies": {
    "express": "^4.17.1",
    "newsapi": "^2.4.1"
  }
}

index.js

/* require newsapi */
const NewsAPI = require('newsapi');
const newsapi = new NewsAPI('YOUR-API-KEY');


/* require express */
const express   = require('express')
const app       = express()

app.get( "/", function( req, res ) {

    // To query sources
    // All options are optional
    newsapi.v2.sources().then( response => {

        console.log( response.sources )

    })

} )

app.listen(4000)

References

npmjs.com/package/newsapi
npmjs.com/package/express

newsapi.org

PHP and MySQL 30: query select

Falah Al Fitri — Mon, 23 Dec 2019 10:02:02 +0000

Happy Coding

`Home` `Previous`

In this post, we will learn about how to use query SELECT in PHP for retrieve data from database MySQL, with 3 ways:

MySQLi procedural
MySQLi object-oriented
PDO

For known, how to connect to database, can be learned in here

Insert query is used for insert data or record into database

Syntax:

    SELECT column1, column2, column3 
    FROM table_name;

using wilcard (*) for select all column

    SELECT *
    FROM table_name;

Example:

    $sql  = "SELECT id, firstname, lastname ";
    $sql .= "FROM users " ;

    $sql  = "SELECT * ";
    $sql .= "FROM users " ;

And, for execute the query, we will use 3 ways:

1. MySQLi¹ procedural

Back to Home

Execute query using mysqli::query² and get a $result:

    $result = mysqli_query( $connection, $sql );

Display data using mysqli_result::fetch_assoc³, alternative using mysqli_result::fetch_object⁴:

    echo "<pre>";

    echo "No \t";
    echo "ID \t";
    echo "Firstname \t\t";
    echo "Lastname \n";

    $no = 1; /* variabel $no */

    /* loop while */
    while ( $row = mysqli_fetch_assoc($result) )
    {

        echo $no . "\t";
        echo $row['id'] . "\t";
        echo $row['firstname'] . "\t\t";
        echo $row['lastname'] . "\n";

        $no++; /* increment */

    }

    echo "</pre>";

Close connection using mysqli::close⁵:

    mysqli_close($connection);

Source Code:

repl.it/antelove19/MySQLi/procedural/select

2. MySQLi¹ object-oriented

Back to Home

Execute query using mysqli::query² and get a $result:

    $result = $connection->query($sql);

Display data using mysqli_result::fetch_object⁴:

    echo "<pre>";

    echo "No \t";
    echo "ID \t";
    echo "Firstname \t";
    echo "Lastname \n";

    $no = 1; /* variabel $no */

    /* loop while */
    while ( $row = $result->fetch_object() )
    {

        echo $no . "\t";
        echo $row->id . "\t";
        echo $row->firstname . "\t\t";
        echo $row->lastname . "\n";

        $no++; /* increment */

    }

    echo "</pre>";

Close connection using mysqli::close⁵:

     $connection->close();

Source Code:

repl.it/antelove19/MySQLi/object-oriented/select

3. PDO⁶

Back to Home

Execute query and get a $result:

    $result = $connection->query($sql);

Display Data:

    echo "<pre>";

    echo "No \t";
    echo "ID \t";
    echo "Firstname \t";
    echo "Lastname \n";

    $no = 1; /* variabel $no */

    /* loop foreach */
    foreach ( $result as $row  )
    {

        echo $no . "\t";
        echo $row->id . "\t";
        echo $row->firstname . "\t\t";
        echo $row->lastname . "\n";

        $no++; /* increment */

    } 

    echo "</pre>";

Close connection:

    $connection = null;

Source Code:

repl.it/antelove19/PDO/select

`Back to Home` | `Next#`

Thank for reading :)

php.net, "MySQL Improved Extension", accessed on date 21 december 2019 and from https://www.php.net/manual/en/book.mysqli.php ↩
php.net, "mysqli::query", accessed on date 22 december 2019 and from https://www.php.net/manual/en/mysqli.query.php ↩
php.net, "mysqli_result::fetch_assoc", accessed on date 23 december 2019 and from https://www.php.net/manual/en/mysqli-result.fetch-assoc.php ↩
php.net, "mysqli_result::fetch_object", accessed on date 23 december 2019 and from https://www.php.net/manual/en/mysqli-result.fetch-object.php ↩
php.net, "mysqli::close", accessed on date 21 december 2019 and from https://www.php.net/manual/en/mysqli.close.php ↩
php.net, "PDO::__construct", accessed on date 21 december 2019 and from https://www.php.net/manual/en/pdo.construct.php ↩

PHP and MySQL 20: query insert

Falah Al Fitri — Sun, 22 Dec 2019 07:30:04 +0000

Happy Coding

`Home` `Previous`

In this post, we will learn how to use query INSERT in PHP for store data into database MySQL, with 3 ways:

MySQLi procedural
MySQLi object-oriented
PDO

For known, how to connect to database, can be learned in here

Insert query is used for insert data or record into database

Syntax:

    INSERT INTO table_name (column1, column2, column3, ...)
    VALUES (value1, value2, value3, ...);

Example:

    $sql  = "INSERT INTO users ";
    $sql .= "( ";
    $sql .= "firstname ";
    $sql .= "lastname ";    
    $sql .= ") ";

    $sql .= "VALUES ";
    $sql .= "( ";
    $sql .= "'John' "; // string, so we must add quote
    $sql .= "'Doe' "; // string    
    $sql .= ")";

And, for execute the query, we will use 3 ways:

1. MySQLi¹ procedural

Back to Home

Execute query using mysqli::query² and get a $result:

    $result = mysqli_query( $connection, $sql );

Check the $result,
if TRUE, call mysqli::$insert_id³ function for get last id inserted and display a success message,
else display error messages using mysqli::$error⁴:

    if ( $result ) // if TRUE
    {

        $id = mysqli_insert_id($connection);

        echo "Data has been <b>CREATED</b> with ID {$id} ..";

    }
    else 
    {

        echo "Error: {$sql}";
        echo "<br />";
        echo "Error: " . mysqli_error($connection);

    }

Close connection using mysqli::close⁵:

    mysqli_close($connection);

Source Code:

repl.it/antelove19/MySQLi/procedural/insert

2. MySQLi¹ object-oriented

Back to Home

Execute query using mysqli::query² and get a $result:

    $result = $connection->query($sql);

Check the $result:

    if ( $result ) // if TRUE
    {

        $id = $connection->insert_id;

        echo "Data has been <b>CREATED</b> with ID {$id} ..";

    } 
    else 
    {

        echo "Error: {$sql}";
        echo "<br />";
        echo "Error: {$connection->error}";

    }

Close connection using mysqli::close⁵:

     $connection->close();

Source Code:

repl.it/antelove19/MySQLi/object-oriented/insert

3. PDO⁶

Back to Home

Execute query and get a $result:

    $result = $connection->query($sql);

Check the $result:

    if ( $result ) // if TRUE
    {

        /* last id insert */
        $id = $connection->lastInsertId();

        echo "Data has been <b>CREATED</b> with ID {$id} ..";

    } 
    else 
    {

        echo "Error: {$sql}";
        echo "<br />";
        echo "Error: {$connection->error}";

    }

Close connection:

    $connection = null;

Source Code:

repl.it/antelove19/PDO/insert

`Back to Home` | `Next`

Thank for reading :)

php.net, "MySQL Improved Extension", accessed on date 21 december 2019 and from https://www.php.net/manual/en/book.mysqli.php ↩
php.net, "mysqli::query", accessed on date 22 december 2019 and from https://www.php.net/manual/en/mysqli.query.php ↩
php.net, "mysqli::$insert_id", accessed on date 22 december 2019 and from https://www.php.net/manual/en/mysqli.insert-id.php ↩
php.net, "mysqli::$error", accessed on date 22 december 2019 and from https://www.php.net/manual/en/mysqli.connect-error.php ↩
php.net, "mysqli::close", accessed on date 21 december 2019 and from https://www.php.net/manual/en/mysqli.close.php ↩
php.net, "PDO::__construct", accessed on date 21 december 2019 and from https://www.php.net/manual/en/pdo.construct.php ↩

PHP and MySQL 11: connection to database

Falah Al Fitri — Sun, 22 Dec 2019 04:54:51 +0000

Happy Coding

`Home` `Previous`

In this post, we will learn about how to create connection to database between PHP as server-side with MySQL as database-engine.

There are 3 ways that will we use:

MySQLi procedural
MySQLi object-oriented
PDO

First, create a PHP file with standar name, like index.php, then write the needed variables:

    $hostname = "localhost";
    $port     = "3306";

    $username = "root";
    $password = "";

Add $database variable:

    $database = "testing";

Then, we will create a database "testing":

    CREATE DATABASE `testing`;

Create table "users":

    CREATE TABLE `users` (
      `id` int(11) NOT NULL,
      `firstname` varchar(50) NOT NULL,
      `lastname` varchar(50) NOT NULL,
      `description` varchar(250) NOT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Add primary key:

    ALTER TABLE `users`
      ADD PRIMARY KEY (`id`);

Add auto increment:

    ALTER TABLE `users`
      MODIFY `id` int(11) NOT NULL AUTO_INCREMENT;
    COMMIT;

1. MySQLi¹ procedural

Back to Home

Create connection using mysqli::__construct², add $database:

    $connection = mysqli_connect( $hostname, $username, $password, $database );

Check connection, if there is errors, call mysqli_connect_error()³ function inside exit()⁴ function and use var_dump()⁵ function with argument of the $connection for get the result:

    if ( ! $connection ) 
    {

        exit( "Connection failed: " . mysqli_connect_error() );

    }
    else
    {

        echo "Connnected succesfully to server";

        echo "<pre>";
        var_dump($connection);
        echo "</pre>";

    }

Close connection using mysqli::close⁶:

    mysqli_close($connection);

Source Code:

repl.it/antelove19/MySQLi/procedural/connection/database ___

2. MySQLi¹ object-oriented

Back to Home

Create connection and add $database:

    $connection = new mysqli( $hostname, $username, $password, $database );

Check connection:

    if ( $connection->connect_error ) 
    {

        exit( "Connection failed: {$connection->connect_error}" );

    }
    else
    {

        echo "Connnected succesfully to server";

        echo "<pre>";
        var_dump($connection);
        echo "</pre>";

    }

Close connection:

    $connection->close();

Source Code:

repl.it/antelove19/MySQLi/object-oriented/connection/database ___

3. PDO⁷

Back to Home

Especially for PDO, we will use try catch

    try
    {

Set dsn and attribute [option], add $database:

        $dsn = "mysql:host=$hostname;port=$port;dbname=$database";

        $setAttribute = array(
            PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'",
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_OBJ
        );

Create connection using PDO::__construct⁸:

        $connection = new PDO( $dsn, $username, $password, $setAttribute );

Check connection:

        if ( $connection ) 
        {

            echo "Connnected succesfully to server";

            echo "<pre>";
            var_dump($connection);
            echo "</pre>";

        }

    }

Get and print error message, if exist:

    catch ( PDOException $err )
    {

        echo "Connection failed: " . $err->getMessage();

    }

Close connection with set $connection equal to null:

    $connection = null;

Source Code:

repl.it/antelove19/PDO/connection/database ___

`Back to Home` | `Next#`

Thank for reading :)

php.net, "MySQL Improved Extension", accessed on date 21 december 2019 and from https://www.php.net/manual/en/book.mysqli.php ↩
php.net, "mysqli::__construct", accessed on date 21 december 2019 and from https://www.php.net/manual/en/mysqli.construct.php ↩
php.net, "mysqli_connect_error", accessed on date 21 december 2019 and from https://www.php.net/manual/en/mysqli.connect-error.php ↩
php.net, "exit", accessed on date 21 december 2019 and from https://www.php.net/manual/en/function.exit.php ↩
php.net, "var_dump", accessed on date 21 december 2019 and from https://www.php.net/manual/en/function.var-dump.php ↩
php.net, "mysqli::close", accessed on date 21 december 2019 and from https://www.php.net/manual/en/mysqli.close.php ↩
php.net, "PHP Data Objects", accessed on date 21 december 2019 and from https://www.php.net/manual/en/book.pdo.php ↩
php.net, "PDO::__construct", accessed on date 21 december 2019 and from https://www.php.net/manual/en/pdo.construct.php ↩

DEV Community: Falah Al Fitri

Axios return async await

Installing

NodeJS request

Request - Simplified HTTP client

request

Example request

Example request callback

Example request promise

Example request promise return

Example request async/await

Javascript: Async/Await

Async Syntax

Example

1

2 Display

Await Syntax

Example

1

2 Display

3 Waiting for a file

4 Waiting for a file - return

Async Function (developer.mozilla.org)

JavaScript: Promise

Promise Syntax

Promise Object Properties

Example promise

Example promise return

Example promise return resolve

Waiting for a Timeout

Waiting for a file

Promise (developer.mozilla.org)

JavaScript: Asynchronous

Example

Note

Waiting for a Timeout

Waiting for Intervals

Waiting for a file

Javascript: Callback

Example

Note

Waiting for a file

JavaScript Sorting Arrays

Array

Numeric Sort

HTML Table rowspan colspan

Cell that spans two rows

Cell that spans two columns

Embed replt

API newsapi.org | Express | for beginner

package.json

index.js

References

PHP and MySQL 30: query select

Happy Coding

Home Previous

1. MySQLi1 procedural

2. MySQLi1 object-oriented

3. PDO6

Back to Home | Next#

PHP and MySQL 20: query insert

Home Previous

1. MySQLi1 procedural

2. MySQLi1 object-oriented

3. PDO6

Back to Home | Next

PHP and MySQL 11: connection to database

Home Previous

1. MySQLi1 procedural

2. MySQLi1 object-oriented

3. PDO7

Back to Home | Next#

`Home` `Previous`

1. MySQLi¹ procedural

2. MySQLi¹ object-oriented

3. PDO⁶

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1. MySQLi¹ procedural

2. MySQLi¹ object-oriented

3. PDO⁶

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`Home` `Previous`

1. MySQLi¹ procedural

2. MySQLi¹ object-oriented

3. PDO⁷

`Back to Home` | `Next#`