Instrumented code for code coverage is not getting parsed correclty

[tamagosante]

#547 addresses a related issue.
(other related: aurelia/testing#94)

Problem

What I found, is that the instrumented code (maybe special to this lib @jsdevtools/coverage-istanbul-loader) is using methods instead of simple properties

⚠️ There is a bug when parsing code, that has coverage-helper-code.
More specifically, aurelia-validation does not parse the helper code correctly aurelia/testing#94.
I found a fix, but would need to PR to the aurelia repo and stuff.
(Maybe we just fork ourselves, will create a ticket)

function (a) {
-    cov_2n0ovlwwxg.f[2]++;    // "normally"
+    cov_2n0ovlwwxg().f[2]++;   // maybe only @jsdevtools/coverage-istanbul-loader?
    return a.message;
}

Suggested fix

A fix I found is to update the parts of the regex by including () (open and close paren)

export function getAccessorExpression(fn: string): string {
  /* tslint:disable:max-line-length */
-  const classic = /^function\s*\([$_\w\d]+\)\s*\{(?:\s*"use strict";)?(?:[$_\s\w\d\/\*.['"\]+;]+)?\s*return\s+[$_\w\d]+\.([$_\w\d]+)\s*;?\s*\}$/;
+  const classic = /^function\s*\([$_\w\d]+\)\s*\{(?:\s*"use strict";)?(?:[$_\s\w\d\/\*.['"\]+();]+)?\s*return\s+[$_\w\d]+\.([$_\w\d]+)\s*;?\s*\}$/;
                                                                                              ^ actual change here

---

Keywords:
@jsdevtools/coverage-istanbul-loader
code coverage instrumented code

[bigopon]

@hiaux0 there @hiaux0 there are existing tests here

validation/test/property-accessor-parser.ts

Lines 47 to 54 in 862da07

	expect(parse('function(a){__gen$field.f[\'10\']++;__aGen$field.g[\'10\']++;return a.b;}'))
	.toEqual('b');
	// tslint:disable-next-line:max-line-length
	expect(parse('function(a){"use strict";_gen$field.f[\'10\']++;_aGen$field.g[\'10\']++;return a.b;}'))
	.toEqual('b');
	// tslint:disable-next-line:max-line-length
	expect(parse('function(a){/* istanbul ignore next */ cov_1wjh4ld5ut.f[9]++;cov_1wjh4ld5ut.s[50]++;return a.b;}'))
	.toEqual('b');

It seems the fix is already figured out, can you help create a PR with some tests @hiaux0 ?

[tamagosante]

@bigopon

existing tests

Afai can see, it fixes just for normal properties, and not methods, ie.

- __gen$field.f[\'10\']
+ __gen$field().f[\'10\'] // I'm expecting `()`

create a PR

yeah, I planned to when I find some spare time