From c66950e93c536181be50e83407f137d715f467e8 Mon Sep 17 00:00:00 2001
From: "Benjamin E. Coe" <bencoe@google.com>
Date: Wed, 1 May 2019 23:01:00 -0700
Subject: [PATCH] feat: add support for ignoring lines, functions, and blocks
 (#87)

---
 README.md                       | 43 +++++++++++++++++++++++++++------
 package-lock.json               |  6 ++---
 package.json                    |  2 +-
 test/fixtures/c8-ignore-next.js | 22 +++++++++++++++++
 test/integration.js             | 14 +++++++++++
 test/integration.js.snap        | 14 +++++++++++
 6 files changed, 89 insertions(+), 12 deletions(-)
 create mode 100644 test/fixtures/c8-ignore-next.js

diff --git a/README.md b/README.md
index 5020fdab..f0dcc709 100644
--- a/README.md
+++ b/README.md
@@ -44,20 +44,47 @@ To check thresholds on a per-file basis run:
 c8 check-coverage --lines 95 --per-file
 ```
 
+## Ignoring Uncovered Lines, Functions, and Blocks
+
+Sometimes you might find yourself wanting to ignore uncovered portions of your
+codebase. For example, perhaps you run your tests on Linux, but
+there's some logic that only executes on Windows.
+
+To ignore lines, blocks, and functions, use the special comment:
+
+`/* c8 ignore next */`.
+
+### Ignoring the next element
+
+```js
+const myVariable = 99
+/* c8 ignore next */
+if (process.platform === 'win32') console.info('hello world')
+```
+
+### Ignoring the next N elements
+
+```js
+const myVariable = 99
+/* c8 ignore next 3 */
+if (process.platform === 'win32') {
+  console.info('hello world')
+}
+```
+
+### Ignoring a block on the current line
+
+```js
+const myVariable = 99
+const os = process.platform === 'darwin' ? 'OSXy' /* c8 ignore next */ : 'Windowsy' 
+```
+
 ## Supported Node.js Versions
 
 c8 uses
 [bleeding edge Node.js features](https://github.com/nodejs/node/pull/22527),
 make sure you're running Node.js `>= 10.12.0`.
 
-## Goals of the Project
-
-A fully functional code coverage solution using only V8's native coverage
-features and minimal user-land modules, so that we fit these constraints:
-
-* No parsing of JavaScript code.
-* No mucking with Node.js' runtime environment.
-
 ## Contributing to `c8`
 
 See the [contributing guide here](./CONTRIBUTING.md).
diff --git a/package-lock.json b/package-lock.json
index fb454ca4..0051565e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -3744,9 +3744,9 @@
       "dev": true
     },
     "v8-to-istanbul": {
-      "version": "3.0.1",
-      "resolved": "https://registry.npmjs.org/v8-to-istanbul/-/v8-to-istanbul-3.0.1.tgz",
-      "integrity": "sha512-pJkVsOvClKyXS23MIysPo1IZI99jrx+0De6LpYw31o+eR/dIGffce7RpwT+PQKbF3tsVrQHvjbxjbVrhaXz5DA==",
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/v8-to-istanbul/-/v8-to-istanbul-3.1.1.tgz",
+      "integrity": "sha512-eHpQJtskRnviG5/OHIUmj9vrUqPDO5WY0MGAuILKSgL6f8x4AVHxpFxCmXFshHw5zhOOznP6VRtxPr+6lNoK+w==",
       "requires": {
         "convert-source-map": "^1.6.0"
       }
diff --git a/package.json b/package.json
index feed27ae..0fb3ec29 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
     "istanbul-reports": "^2.0.0",
     "rimraf": "^2.6.2",
     "test-exclude": "^5.0.0",
-    "v8-to-istanbul": "^3.0.1",
+    "v8-to-istanbul": "^3.1.1",
     "yargs": "^13.1.0",
     "yargs-parser": "^10.1.0"
   },
diff --git a/test/fixtures/c8-ignore-next.js b/test/fixtures/c8-ignore-next.js
new file mode 100644
index 00000000..606fadbf
--- /dev/null
+++ b/test/fixtures/c8-ignore-next.js
@@ -0,0 +1,22 @@
+const a = 99
+const b = true ? 1 /* c8 ignore next */ : 2
+if (true) {
+  console.info('covered')
+/* c8 ignore next 3 */
+} else {
+  console.info('uncovered')
+}
+
+/* c8 ignore next */
+if (false) console.info('uncovered')
+
+/* c8 ignore next 3 */
+function notExecuted () {
+
+}
+
+if (true) {
+  console.info('covered')
+} else { /* c8 ignore next */
+  console.info('uncovered')
+}
diff --git a/test/integration.js b/test/integration.js
index 7e8feb4d..e3300067 100644
--- a/test/integration.js
+++ b/test/integration.js
@@ -172,6 +172,20 @@ describe('c8', () => {
     })
   })
 
+  describe('/* c8 ignore next */', () => {
+    it('ignores lines with special comment', () => {
+      const { output } = spawnSync(nodePath, [
+        c8Path,
+        '--exclude="test/*.js"',
+        '--clean=false',
+        '--temp-directory=tmp/normal',
+        nodePath,
+        require.resolve('./fixtures/c8-ignore-next.js')
+      ])
+      output.toString('utf8').should.matchSnapshot()
+    })
+  })
+
   describe('source-maps', () => {
     beforeEach(cb => rimraf('tmp/source-map', cb))
 
diff --git a/test/integration.js.snap b/test/integration.js.snap
index 95b0e99b..0983a0b7 100644
--- a/test/integration.js.snap
+++ b/test/integration.js.snap
@@ -1,5 +1,19 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`c8 /* c8 ignore next */ ignores lines with special comment 1`] = `
+",covered
+covered
+-------------------|----------|----------|----------|----------|-------------------|
+File               |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
+-------------------|----------|----------|----------|----------|-------------------|
+All files          |    86.21 |    91.67 |    66.67 |    86.21 |                   |
+ async.js          |      100 |      100 |      100 |      100 |                   |
+ c8-ignore-next.js |    90.91 |      100 |      100 |    90.91 |             21,22 |
+ normal.js         |       75 |    66.67 |    33.33 |       75 | 14,15,16,18,19,20 |
+-------------------|----------|----------|----------|----------|-------------------|
+,"
+`;
+
 exports[`c8 ESM Modules collects coverage for ESM modules 1`] = `
 ",bar foo
 ------------|----------|----------|----------|----------|-------------------|