It seems that isProtoString will always return false?

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
35/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
javascript
Domain
tooling

Research direction

Start in lib/util.js at isProtoString, using the linked implementation and its callers to determine which strings the function is intended to recognize. Reproduce the reported behavior with representative inputs and inspect existing tests or test commands; done means the predicate returns the intended result and has regression coverage.

Written by the indexing model from the issue text.

Description

https://github.com/mozilla/source-map/blob/58819f09018d56ef84dc41ba9c93f554e0645169/lib/util.js#L66

function isProtoString(s) {
  if (!s) {
    return false;
  }

  const length = s.length;

  if (length < 9 /* "__proto__".length */) {
    return false;
  }

  /* eslint-disable no-multi-spaces */
  if (
    s.charCodeAt(length - 1) !== 95 /* '_' */ ||
    s.charCodeAt(length - 2) !== 95 /* '_' */ ||
    s.charCodeAt(length - 3) !== 111 /* 'o' */ ||
    s.charCodeAt(length - 4) !== 116 /* 't' */ ||
    s.charCodeAt(length - 5) !== 111 /* 'o' */ ||
    s.charCodeAt(length - 6) !== 114 /* 'r' */ ||
    s.charCodeAt(length - 7) !== 112 /* 'p' */ ||
    s.charCodeAt(length - 8) !== 95 /* '_' */ ||
    s.charCodeAt(length - 9) !== 95 /* '_' */
  ) {
    return false;
  }
  /* eslint-enable no-multi-spaces */

  for (let i = length - 10; i >= 0; i--) {
    if (s.charCodeAt(i) !== 36 /* '$' */) {
      return false;
    }
  }

  return true;
}
Dominant language
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