jquery / jquery/esprima

Invalid UpdateExpression's arguments

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TypeScript
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Description

Invalid UpdateExpression's arguments

Esprima' UpdateExpression's argument is one of: ObjectExpression, ArrayExpression, MemberExpression, Identifier.

Consider behaviour of V8:
image

Should be:
Argument of UpdateExpression is one of: Identifier, MemberExpression

Steps to reproduce
esprima.parse('--[]') // or --{}, []--, (++[]), etc.
Expected output

Expected "Invalid left-hand side expression in prefix operation"

Actual output
{
  "type": "UpdateExpression",
  "operator": "--",
  "argument": {
    "type": "ArrayExpression",
    "elements": []
  },
  "prefix": true
}
Relevant references

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First steps

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  4. Open a pull request that references the issue number.

Research direction

No source file or test is named in the issue. Reproduce the listed --[] and --{} cases in Esprima, locate the UpdateExpression parser entry point, and compare its accepted argument types with the expected syntax error. Done means invalid operands are rejected while Identifier and MemberExpression operands still parse.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, typescript
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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