How to evaluate a string on a regular expression rule in JavaScript

-

JavaScript has a built in regular expression function for testing if a string arguments is matching the given regular expression rule;

Syntax of the regular expression tester is as follows;

/regex/.test(string)

Take for instance you want to test if a string contains only alphanumeric upper and lower case characters, space and numbers;

const str = "Eat code sleep"

/[A-Z,a-z,0-9, ]*/.test(str)
// returns boolean 'true'

Or in another example;

const str = "Eat, Code, Sleep"

/[A-Z,a-z,0-9, ]*/.test(str)
// returns boolean 'false'

Because commas are not included in the regular expression match rules.

Comments

Post a Comment

Popular posts from this blog

E2020 dynamic imports in JavaScript

-
Escmascript Is a standard from which JavaScript and typescript are both derived from. ES2020 is out it comes with it new ways of writing JavaScript code. Dynamic imports enable importing dependencies in a rather dynamic way. Initially JavaScript developers were restricted to statically load their dependencies for instance; import { property } from 'dependency' On runtime the JavaScript engine loads the required dependencies and makes them accessible globally. However that is a rigid way of writing code. Dynamic imports are  relatively more flexible therefore you can included them at any segment within your program. For instance if you want to load file system module only if a certain criteria is met you would do as follows; If(process.argv[2] == 'start') Import fs from 'fs' Dynamic imports return a promise use the syntax below to make use of them import('fs') .then(fs => {    // consume module fs })
Read more

how to dump a postgresql database using from the terminal

-
PostgreSQL is a relational database management system and arguably the best database management around. postgreSQL comes with utilities used to manipulate databases from the terminal "psql" being the most popular utility I'm sure you've read somewhere or used "psql" dumping "backing" databases is done using PostgreSQL's pg_dump utility In your terminal type; pg_dump <database name> > <output> For instance to backup a database named "books" to a file named "books.sql" do; pg_dump "books" > books.sql How to exclude database data from backups To exclude database data from your output file you should include "-s" flag in your command pg_dump -s "books" > books.sql
Read more

JavaScript intro to classes

-
Classes are objects 'functions which introduce inheritance parent child relationship in JavaScript it promotes code reusability which reduces the amount of code in a JavaScript application. JavaScript class decelerations start with keyword class proceeded by class name with a class body having a constructor along with methods for instance class human {     constructor(name) {          this.name = name;          this.gender = null;     }     great() {         return "Greetings " +         (this.gender == "male") ? "mr " : "mrs " + this.name     } } Child classes are created by adding the keyword extends followed by the parent class name and parent class methods can be called using the syntax super.+"method name"(parameters) class man extends human {   ...
Read more

Tar basic commands to store and extract files

-
Targeted is an archiving program designed to package, store, and compress multiple files into a single portable package the name tar is an abbreviation for tape archiver Apart from creating .tar archives tar is also capable of compressing files using zip, bzip2, and gzip compression algorithms Tar flags c — compress directive x — extract directive t — tabulate contents f — specify filename z — use zip/gzip compression j — use bzip2 compression k — do not overwrite t — files from file w — ask for configuration v — verbose gzip flags d — decompress file Tar commandline commands syntax tar -{arguments} {params} Example tar commands tar -cf music.tar music.mp3 Tar archiver will be directed to compress music.mp3 into a tar archive named music.tar and save it in the current working directory tar -xf music.tar Tar will be directed to extract music.tar archive and save the constituent contents of the archive...
Read more

FlappingBird JS13K Games

-
Image
FlappingBird is a Mobile side scroller game where the player controls a bird, attempting to fly between columns trees without hitting them Development of this game started out when i was attempting to draw perfect clouds programmatically on a canvas i later added a few more clouds (Something's missing) add moon, stars,  buildings and also add Gradients and for the games character i settled on a bird (using Sprite sheet obtained freely from opengameart) add more them and animated everything. FlappingBird is a single player arcade-style game in which the player controls the bird, which moves persistently to the right. The player is tasked with navigating the bird through pairs of trees that have equally sized gaps placed at random heights. the bird automatically gravitates and only ascends when the player taps the touchscreen or spacebar. Each successful pass through a pair of trees awards the player one point. Colliding with a tree or the ground ends the gamepl...
Read more