Ways to iterate array items in JavaScript

-

A few days ago i introduced arrays and described what they are and how their elements can be iterated in JavaScript using 'for loop'

There many other ways to iterate arrays namely Array.forEach, Array.map,
var array = ['eat', 'code', 'sleep']

Using forEach
array.forEach(function(value, index){
    console.log(index + ': '+ value)
})

// result expected
// 0: "eat"
// 1: "code"
// 2: "sleep"

Using Array.map
array.map(function(value, index){
    console.log(index + ': '+ value)
})

// result expected
// 0: "eat"
// 1: "code"
// 2: "sleep"

It's a wrapp

Comments

Post a Comment

Popular posts from this blog

How to wait for a promise within a loop block

-
JavaScript promises enable developers to write asynchronous applications in JavaScript Loops are ways of iterating elements For instance doing an asynchronous task within a for loop can be done as follows; Note that lag is used to emulate some delay. const items = [1, 2, 3, 4] const lag = async (delay) => {     return new Promise((resolve) =>         setTimeout(() => res(`${delay / 1000} sec`), delay)) } items.forEach(async (item) => {     const seconds = await lag(1000 * item)     console.log(seconds) }) expected output 1 sec 2 sec 3 sec 4 sec After running the code above every second some text was printed
Read more

Removing bash.sh #hash comments from a string using regEx in JavaScript

-
Last night i was looking for a method to remove comments from a robots.txt file containing contents of form below `# robots.txt user-agent Disallow:` Or a more practical format obtained by splitting the robots.txt file line by line. ["# robots.txt", "user-agent", "Disallow:"] every element of the array is a string representing a single line of text from a robots.txt plain text file. Regular expression I used regular expression to strip out the unwanted text until the end of the line however it's not limited to robots.txt it works perfectly with bash.sh files as well. Example var string = "Disallow / #deny bots" string.replace(/#.*$/, "") // returns  Disallow / It simply strip's off all characters after the hash character until the end of the line.
Read more

Snake monochrome (JS1024)

-
JS1024 is an annually held code golfing competition where you're basically required to create something creative in 1024 bytes or less of raw "JavaScript/HTML/WebGL" I participated for JS1024 2020 competition with my First entry titled "Snake monochrome" Originally inspired by the old Nokia game going by the same name "Snake" which i used to play as far back as 2007-2008 Another entry making it Second is named "Tetris monochrome" i was compiled to do this game as a dare from my Girlfriend on June 6 the "Tetris 1984" anniversary Third one is F1-racer it's inspired by my bestfriend who wasn't impressed with how i hooked up controls on "Tetris Monochrome" so he requested "i modify controls a bit", and i improved "input/output" by adding smooth touch input to it as requested Snake game contains two entities. The Snake and the Apple, the Snake is an Object with properties position (vect...
Read more

How to set content disposition headers for express nodejs apps

-
Image
In express nodejs apps you can force the user agent "browser" to rather download content instead of displaying or attempting to render given content within the browser. In this example assuming you're using express.static to serve content pass an Object as second argument to express.static function An Object with configuration parameters; const config = { setHeaders: res => res.set('Content-disposition',  'attachment') } In your code replace "path/to/media/" with the path pointing to the static content. app.use('/media/', express.static('path/to/media/', config)) To test try accessing content at /media/*
Read more

Es6 new features summarized round up

-
Escmascript es2017 or better known as es16 is the edition after the famously popular es15, In this edition there are only two new additional features the exponention operator and Array.prototype.includes() function exponention operator ** Operator is a short hand method used for raising numbers to their power Its syntax is similar to native operators such as '+' Addition and '-' (minus) for subtraction Example usage Initially to raise a number to the power you would need to use math library pow function as; Math.pow({number}, {factor}) Since es2017 you can simplify the operation above down to simply as; {number} ** {factor} Example as; 5 ** 2 // Giving you 25 Array.prototype.includes () Array includes is a feature similar to a pre existing function array.indexof() as compared to array.indexof() array.includes() function notably returns a true  boolean on matched value, and false if value not matched Examples on how to use 'array.includes ()' funct...
Read more