Coverage

Shell

esdev test --coverage

TEXT

---------------|---------|----------|---------|---------|-------------------
 File          | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
---------------|---------|----------|---------|---------|-------------------
 All files     |   66.66 |     37.5 |      80 |   69.23 |
 src/labels.js |     100 |       50 |     100 |     100 |
 src/math.ts   |      50 |       25 |   66.66 |   57.14 | 7-8,10
---------------|---------|----------|---------|---------|-------------------

The run prints this table and writes coverage/lcov.info, which genhtml, Codecov and most CI services read. The measures are Istanbul's, so the numbers compare with what Vitest and Jest report.

Coverage is measured on the files as you wrote them. TypeScript is counted on its own lines, not on the JavaScript it runs as. No code is instrumented: V8 counts what runs, the same way Vitest's default v8 provider works.

Configuration

Settings live in esdev.json, under test.coverage:

JSON

{
  "test": {
    "coverage": {
      "enabled": true,
      "include": ["src"],
      "exclude": ["src/generated"],
      "reporter": ["text", "lcov", "json-summary"],
      "reportsDirectory": "coverage",
      "thresholds": { "lines": 90, "branches": 80, "functions": -5 }
    }
  }
}

Key
`enabled`	Collect on every run, without `--coverage`. Default `false`.
`include`	Globs of the files to report, relative to the project. A pattern with no wildcard is a directory. By default, only files the tests loaded are reported; with `include`, a matching file no test loaded is reported at 0%.
`exclude`	Globs of files to leave out. Test files, setup modules and `node_modules` are always left out.
`reporter`	`text` (the table), `lcov` (`lcov.info`), `json` (Istanbul's `coverage-final.json`) and `json-summary` (`coverage-summary.json`). Default `["text", "lcov"]`.
`reportsDirectory`	Where the report files go. Default `coverage`.
`thresholds`	`lines`, `branches`, `functions`, `statements`. A positive number is the least percentage; a negative one is how many may be uncovered. A run below a threshold fails, even when every test passed.

With a machine reporter such as --reporter=json, the table goes to stderr so stdout keeps only the report.

Ignoring code

A comment leaves code out of the measures. The spellings of V8, c8 and Istanbul all work:

TypeScript

/* v8 ignore next */
function debugOnly() {}

/* v8 ignore start */
if (verbose) {
  trace();
}
/* v8 ignore stop */

next leaves out the statement, function or branch that follows the comment. start and stop leave out everything between them.

Where it runs

Coverage works with --watch (a report after each run), --file, --shard and --changed. It is not collected in --browser runs, which run in another engine, or with --isolation=none. Passing --coverage there is an error. When the project turns it on with enabled, those runs go without it and say so.

What it cannot see

Only code the tests import is measured. A file started as a separate process, or read and evaluated at run time, is not.