feat: adds --all functionality (bcoe#158)

Author: j03m

.gitignore

@@ -3,3 +3,4 @@ node_modules
 .nyc_output
 coverage
 tmp
+.idea

README.md

@@ -16,6 +16,16 @@ c8 node foo.js
 
 The above example will output coverage metrics for `foo.js`.
 
+## Checking for "full" source coverage using `--all`
+
+By default v8 will only give us coverage for files that were loaded by the engine. If there are source files in your 
+project that are flexed in production but not in your tests, your coverage numbers will not reflect this. For example,
+if your project's `main.js` loads `a.js` and `b.js` but your unit tests only load `a.js` your total coverage 
+could show as `100%` for `a.js` when in fact both `main.js` and `b.js` are uncovered.  
+
+By supplying `--all` to c8, all files in `cwd` that pass the `--include` and `--exclude` flag checks, will be loaded into the
+report. If any of those files remain uncovered they will be factored into the report with a default of 0% coverage. 
+
 ## c8 report
 
 run `c8 report` to regenerate reports after `c8` has already been run.

lib/commands/report.js

@@ -19,7 +19,8 @@ exports.outputReport = async function (argv) {
     watermarks: argv.watermarks,
     resolve: argv.resolve,
     omitRelative: argv.omitRelative,
-    wrapperLength: argv.wrapperLength
+    wrapperLength: argv.wrapperLength,
+    all: argv.all
   })
   await report.run()
   if (argv.checkCoverage) checkCoverages(argv, report)

lib/parse-args.js

@@ -83,6 +83,12 @@ function buildYargs (withCommands = false) {
       type: 'boolean',
       describe: 'should temp files be deleted before script execution'
     })
+    .options('all', {
+      default: false,
+      type: 'boolean',
+      describe: 'supplying --all will cause c8 to consider all src files in the current working directory ' +
+        'when the determining coverage. Respects include/exclude.'
+    })
     .pkgConf('c8')
     .config(config)
     .demandCommand(1)

lib/report.js

@@ -3,8 +3,9 @@ const furi = require('furi')
 const libCoverage = require('istanbul-lib-coverage')
 const libReport = require('istanbul-lib-report')
 const reports = require('istanbul-reports')
-const { readdirSync, readFileSync } = require('fs')
-const { isAbsolute, resolve } = require('path')
+const { readdirSync, readFileSync, statSync } = require('fs')
+const { isAbsolute, resolve, extname } = require('path')
+const getSourceMapFromFile = require('./source-map-from-file')
 // TODO: switch back to @c88/v8-coverage once patch is landed.
 const v8toIstanbul = require('v8-to-istanbul')
 const isCjsEsmBridgeCov = require('./is-cjs-esm-bridge')
@@ -19,7 +20,8 @@ class Report {
     watermarks,
     omitRelative,
     wrapperLength,
-    resolve: resolvePaths
+    resolve: resolvePaths,
+    all
   }) {
     this.reporter = reporter
     this.reportsDirectory = reportsDirectory
@@ -33,6 +35,8 @@ class Report {
     this.omitRelative = omitRelative
     this.sourceMapCache = {}
     this.wrapperLength = wrapperLength
+    this.all = all
+    this.src = process.cwd()
   }
 
   async run () {
@@ -56,8 +60,8 @@ class Report {
     // use-case.
     if (this._allCoverageFiles) return this._allCoverageFiles
 
+    const map = libCoverage.createCoverageMap()
     const v8ProcessCov = this._getMergedProcessCov()
-    const map = libCoverage.createCoverageMap({})
     const resultCountPerPath = new Map()
     const possibleCjsEsmBridges = new Map()
 
@@ -94,7 +98,6 @@ class Report {
         map.merge(converter.toIstanbul())
       }
     }
-
     this._allCoverageFiles = map
     return this._allCoverageFiles
   }
@@ -139,14 +142,50 @@ class Report {
   _getMergedProcessCov () {
     const { mergeProcessCovs } = require('@bcoe/v8-coverage')
     const v8ProcessCovs = []
+    const fileIndex = new Set() // Set<string>
     for (const v8ProcessCov of this._loadReports()) {
       if (this._isCoverageObject(v8ProcessCov)) {
         if (v8ProcessCov['source-map-cache']) {
           Object.assign(this.sourceMapCache, v8ProcessCov['source-map-cache'])
         }
-        v8ProcessCovs.push(this._normalizeProcessCov(v8ProcessCov))
+        v8ProcessCovs.push(this._normalizeProcessCov(v8ProcessCov, fileIndex))
       }
     }
+
+    if (this.all) {
+      const emptyReports = []
+      v8ProcessCovs.unshift({
+        result: emptyReports
+      })
+      const workingDir = process.cwd()
+      this.exclude.globSync(workingDir).forEach((f) => {
+        const fullPath = resolve(workingDir, f)
+        if (!fileIndex.has(fullPath)) {
+          const ext = extname(f)
+          if (ext === '.js' || ext === '.ts' || ext === '.mjs') {
+            const stat = statSync(f)
+            const sourceMap = getSourceMapFromFile(f)
+            if (sourceMap !== undefined) {
+              this.sourceMapCache[`file://${fullPath}`] = { data: JSON.parse(readFileSync(sourceMap).toString()) }
+            }
+            emptyReports.push({
+              scriptId: 0,
+              url: resolve(f),
+              functions: [{
+                functionName: '(empty-report)',
+                ranges: [{
+                  startOffset: 0,
+                  endOffset: stat.size,
+                  count: 0
+                }],
+                isBlockCoverage: true
+              }]
+            })
+          }
+        }
+      })
+    }
+
     return mergeProcessCovs(v8ProcessCovs)
   }
 
@@ -193,15 +232,17 @@ class Report {
    * There is no deep cloning.
    *
    * @param v8ProcessCov V8 process coverage to normalize.
+   * @param fileIndex a Set<string> of paths discovered in coverage
    * @return {v8ProcessCov} Normalized V8 process coverage.
    * @private
    */
-  _normalizeProcessCov (v8ProcessCov) {
+  _normalizeProcessCov (v8ProcessCov, fileIndex) {
     const result = []
     for (const v8ScriptCov of v8ProcessCov.result) {
       if (/^file:\/\//.test(v8ScriptCov.url)) {
         try {
           v8ScriptCov.url = furi.toSysPath(v8ScriptCov.url)
+          fileIndex.add(v8ScriptCov.url)
         } catch (err) {
           console.warn(err)
           continue

lib/source-map-from-file.js

@@ -0,0 +1,25 @@
+const { isAbsolute, join, dirname } = require('path')
+const { readFileSync } = require('fs')
+/**
+ * Extract the sourcemap url from a source file
+ * reference: https://sourcemaps.info/spec.html
+ * @param {String} file - compilation target file
+ * @returns {String} full path to source map file
+ * @private
+ */
+function getSourceMapFromFile (file) {
+  const fileBody = readFileSync(file).toString()
+  const sourceMapLineRE = /\/\/[#@] ?sourceMappingURL=([^\s'"]+)\s*$/mg
+  const results = fileBody.match(sourceMapLineRE)
+  if (results !== null) {
+    const sourceMap = results[results.length - 1].split('=')[1]
+    if (isAbsolute(sourceMap)) {
+      return sourceMap
+    } else {
+      const base = dirname(file)
+      return join(base, sourceMap)
+    }
+  }
+}
+
+module.exports = getSourceMapFromFile

package-lock.json

@@ -61,4 +61,4 @@
     "bin",
     "LICENSE"
   ]
-}
+}