ECMAScript

• Standard developed by ECMA International

ECMAScript

• Standard developed by ECMA International
• JavaScript, JScript and ActionScript

ECMAScript

• Standard developed by ECMA International
• JavaScript, JScript and ActionScript
• First edition: ECMAScript 1 (1997), latest ECMAScript 2019
• ECMAScript 2019 (also known ES2019 or ES10) 

History

History

• Netscape and Java

History

• Netscape and Java
• Brendan Eich

History

• Netscape and Java
• Brendan Eich
• Mocha -> Livescript -> JavaScript

History

• Netscape and Java
• Brendan Eich
• Mocha -> Livescript -> JavaScript
• Microsoft and JScript

History

• Netscape and Java
• Brendan Eich
• Mocha -> Livescript -> JavaScript
• Microsoft and JScript
• Netscape and ECMA

History

• Netscape and Java
• Brendan Eich
• Mocha -> Livescript -> JavaScript
• Microsoft and JScript
• Netscape and ECMA
• ECMAScript

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)
• ECMAScript 2015 [ES6 or ES2015] (classes, modules, arrow functions, const and let, promises; 2015)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)
• ECMAScript 2015 [ES6 or ES2015] (classes, modules, arrow functions, const and let, promises; 2015)
• ECMAScript 2016 (Array.prototype.includes, exponentiation operator **; 2016)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)
• ECMAScript 2015 [ES6 or ES2015] (classes, modules, arrow functions, const and let, promises; 2015)
• ECMAScript 2016 (Array.prototype.includes, exponentiation operator **; 2016)
• ECMAScript 2017 (async/await; Object.values / entries; 2017)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)
• ECMAScript 2015 [ES6 or ES2015] (classes, modules, arrow functions, const and let, promises; 2015)
• ECMAScript 2016 (Array.prototype.includes, exponentiation operator **; 2016)
• ECMAScript 2017 (async/await; Object.values / entries; 2017)
• ECMAScript 2018 (rest / spread object, async iteration; 2018)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)
• ECMAScript 2015 [ES6 or ES2015] (classes, modules, arrow functions, const and let, promises; 2015)
• ECMAScript 2016 (Array.prototype.includes, exponentiation operator **; 2016)
• ECMAScript 2017 (async/await; Object.values / entries; 2017)
• ECMAScript 2018 (rest / spread object, async iteration; 2018)
• ECMAScript 2019 (flat; 2019)

ECMAScript Versions

• ECMAScript 1 (first standard; 1997)
• ECMAScript 2 (editoral changes; 1998)
• ECMAScript 3 (regular expressions, try catch; 1999)
• ECMAScript 4 (classes, modules, generators, destructuring; ----) 
• ECMAScript 3.1 -> 5 (strict mode, JSON native support; 2009)
• ECMAScript 2015 [ES6 or ES2015] (classes, modules, arrow functions, const and let, promises; 2015)
• ECMAScript 2016 (Array.prototype.includes, exponentiation operator **; 2016)
• ECMAScript 2017 (async/await; Object.values / entries; 2017)
• ECMAScript 2018 (rest / spread object, async iteration; 2018)
• ECMAScript 2019 (flat; 2019)
• ESNext

Who designs ECMAScript?

TC39 (Technical Committee 39)

• https://tc39.es/
• https://github.com/tc39/agendas
• https://github.com/tc39/notes

How ECMAScript is designed?

Stage 0 (Strawman)

Ideas from TC39 members or contributors

https://github.com/tc39/proposals/blob/master/stage-0-proposals.md

Stage 1 (Formal proposal)

Champion, describe feature, high level API

https://github.com/tc39/proposals/blob/master/stage-1-proposals.md

Stage 2 (Draft)

Initial spec text (can includes TODOs / placeholders)

https://github.com/tc39/proposals#stage-2

Stage 3 (Candidate)

Complete spec text, feedback

https://github.com/tc39/proposals#stage-3

Stage 4 (Finished)

Tests (must be passed), ready to include in the standard

https://github.com/tc39/proposals/blob/master/finished-proposals.md

Optional chaining (history)

Optional chaining (history)

Optional chaining (history)

Stage 0

https://docs.google.com/presentation/d/11O_wIBBbZgE1bMVRJI8kGnmC6dWCBOwutbN9SWOK0fU/view#slide=id.g1c161255c9_0_50

Optional chaining (history)

Stage 1

https://claudepache.github.io/es-optional-chaining/

Optional chaining (history)

Stage 2

https://docs.google.com/presentation/d/1iiCtJSW42Z7lg0YlagOZOfI-FTrkN88OuiO3pySawSo/edit#slide=id.g25fec30b35_0_126

Optional chaining (history)

Stage 3

https://onedrive.live.com/view.aspx?resid=5D3264BDC1CB4F5B!5281&ithint=file%2cpptx&authkey=!AH-MOCJRlVtK_QE

Optional chaining (history)

Stage 4

https://tc39.es/proposal-optional-chaining/

Summary

• https://kangax.github.io/compat-table/es6/

Summary

• https://kangax.github.io/compat-table/es6/
• https://tc39.es/process-document/