Comprehending standards notation for JS
summary
A close reading of ECMAScript notation shows how to extract actual behavior: step‑by‑step evaluation of Array.prototype.at and the relative indexing semantics, parsing grammar into member/call expressions, and how coercions and abrupt completions propagate. Test harness work uses test262 (roughly 78k tests) run in browser CI to reveal engine gaps and force spec/tests/implementations to converge; several real inconsistencies and resulting fixes are demonstrated.
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chapters (11)
- 0:00Start
- 20:53Acme Script
- 25:36How a Built-In Works
- 25:56Arrayprototype
- 29:39The Relative Indexing Method
- 38:02Indexing Numbers
- 43:15Syntax
- 43:37Syntax Analysis
- 44:39Binding Separator
- 51:53Saturation of the Code
- 1:11:20Versioning of Javascript
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