Martial martialboniou

Here's some random memos about JavaScript.

Important notes

NaN is a number (?); operators on NaN yields into NaN except in the + case with a string (as below);
IMPORTANT: if we write (x + y) with x as a number and y as a string, it yields into a string (because + is mainly a string concatenation operator); but if + is another math operator (eg: *), it yields into a number; another important case of +: 1 + true yields into 2 because true(otherwise false or null) is converted into 1 (0 respectively); 1 + undefined yield into NaN; "1" + null yields into "1null";
beware of precision issues with floating-point numbers (because JS uses binary form to represent decimal numbers internally); try to remove the floating point (multiply by 10eX where X is a positive integer) then calculate, finally then divide by the same multiplier;
remember the ternary operator: (condition) ? yes : no;
IMPORTANT (of for arrays, strings, in for objects):

Here's some random snippets for a better understanding of Java.

Symfony tutorial

I'd start with this (first app tutorial)[https://auth0.com/blog/creating-your-first-symfony-app-and-adding-authentication/]; it looks obscure (I had to check some additional docs). In this tutorial, you'll create a custom authentication using Symfony Guard. NOTE: don't use: (Symfony tutorial)[https://auth0.com/blog/symfony-tutorial-building-a-blog-part-1]

NOTE: check later:

SQL DIGEST

Basics

Here's some SQL fundamental reminders.

IMPORTANT: DON'T USE utf8; I use utf8mb4_0900_ai_ci;
\G to terminate a SQL statement instead of ; displays the result vertically rather than normal tabular format if they are too wide for the current window;

PHP7 DIGEST

Here's some tips/snippets for PHP7 (knowledge of PHP5 required).

Please install Github Mermaid extension for Firefox/Chrome to display the diagrams in this document.

Useful functions & vars

BOOTSTRAP DIGEST

NOTE: As much as I can I will try to do the bootstrap 4 tutorial and learn BS5. The demos in the root of this directory are BS5; the subdirectory BS4 contains the demos from tutorialrepublic for the stable but soon deprecated BS4