Ecma script version in iTowns

[gchoqueux]

Ecma script 6 in itowns

ITowns is written in ES6 and uses almost all its new features. (See all features).
ITowns is transpiled in ES5 with Babel.

Important code rules, that aren't completely applied:

• Uses Class instead of object.
• Uses Set and Map instead of Array, when relevant.

Little used features, don't forget them :

• Array element finding

[ 1, 3, 4, 2 ].find(x => x > 3) // 4 
[ 1, 3, 4, 2 ].findIndex(x => x > 3) // 2

• String Searching

"hello".startsWith("ello", 1) // true 
"hello".endsWith("hell", 4)  // true 
"hello".includes("ell")  // true

• Number Safety Checking

Number.isSafeInteger(9007199254740992) === false

Ecma script 2016 in itowns see #932

• exponentiation operator (**).
• Array.prototype.includes.

Ecma script 2017

• Includes async/await. (Used in tests)

Ecma script 2018

• New features include rest/spread properties.
• Asynchronous iteration.
• Promise.prototype.finally() .
• additions to RegExp.

Ecma script 2019

What's new in Ecma script 2019

• Array.Flat()
• Object.fromEntries()
• Array.flatMap()
• String.trimStart() & String.trimEnd()
• Optional Catch Binding
• Function.toString()
• Well Formed JSON.Stringify()
• Array.Sort Stability

Ecma script 2020

What's new in Ecma script 2020

• Dynamic imports
• Import meta data
• New export syntax
• BigInt and arbitrary precision integers
• matchAll() method for regular expressions
• globalThis object
• Promise.allSettled() method
• nullish coalescing operator
• Optional chaining

Ecma script 2021

What's new in Ecma script 2021

• string.replaceAll method
• Private Methods
• Private Accessors
• Promise.any()
• Numeric Separators
• Logical Assignment Operator

Ecma script 2022

What's new in Ecma script 2022

• Top-level Await Operator
• Class Field Declarations
• Private Methods and Fields
• Static Class Fields and Private Static Methods
• Regexp Match Indices
• Ergonomic Brand Checks for Private Fields
• Array.at() Function for Indexing
• Scalable Object.prototype.hasOwnProperty()

[jailln]

Good idea.

I think that some of this information (e.g. use class instead of object, etc.) should be added in a to be created 'developer guide' (maybe in the wiki or in the docs folder? and pointed into the CONTRIBUTING.md file).

[zarov]

Thanks for creating this issue ! This can be a good first contribution for anyone wanting to contribute to iTowns.

@jailln yes, in fact the CONTRIBUTING file could be rewritten for a more up-to-date content. If you want to start a draft I'm all for it and then we can discuss it in a PR ?

[jailln]

@zarov yep, I'll start a draft in a new PR with propositions that came up while starting contributing to iTowns.

[mgermerie]

We need to define what rule we should make mandatory (in the ESLint config).