[javascript/fr] Add new js features

[Th3G33k]

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Introduce more js features. #1253

Add :

• Regex
• Ternary conditional operator
• Error handling try ... catch
• Rest parameter (ES6)
• Promise (ES6)
• Async / Await (ES2017)
• Optional chaining operator (ES2020)
• Another syntax for import

Remove :

• Duplicate spread operator (ES6)