feat: add check total script (#3)

```
check-total
# with default options
check-total --from coverage/coverage-summary.json --min 80
```

Author: bahmutov

.github/workflows/ci.yml

@@ -16,6 +16,9 @@ jobs:
           node bin/check-coverage to/main2.js
           node bin/only-covered main1.js main2.js
 
+      - name: Check totals 🛡
+        run: node bin/check-total --min 90
+
       - name: Semantic Release 🚀
         uses: cycjimmy/semantic-release-action@v2
         env:

README.md

@@ -20,5 +20,15 @@ only-covered --from examples/exclude-files/coverage/coverage-final.json main.js
 check-coverage --from examples/exclude-files/coverage/coverage-final.json main.js
 ```
 
+## check-total
+
+If you generate coverage report using reporter `json-summary`, you can check the total statements percentage
+
+```shell
+check-total
+# with default options
+check-total --from coverage/coverage-summary.json --min 80
+```
+
 [ci image]: https://github.com/bahmutov/check-code-coverage/workflows/ci/badge.svg?branch=master
 [ci url]: https://github.com/bahmutov/check-code-coverage/actions

bin/check-total.js

@@ -0,0 +1,39 @@
+#!/usr/bin/env node
+// @ts-check
+const { join, resolve } = require('path')
+const arg = require('arg')
+
+const args = arg({
+  '--from': String, // input json-summary filename, by default "coverage/coverage-summary.json"
+  '--min': Number
+})
+
+const minStatementPercentage = args['--min'] || 80
+const fromFilename = args['--from'] || join('coverage', 'coverage-summary.json')
+const coverageFilename = resolve(fromFilename)
+
+const coverage = require(coverageFilename)
+const total = coverage.total
+if (!total) {
+  console.error('Could not find "total" object in %s', fromFilename)
+  process.exit(1)
+}
+
+// total should have objects for lines, statements, functions and branches
+// each object should have total, covered, skipped and pct numbers
+const statements = total.statements
+if (!statements) {
+  console.error('Could not find statements in total %o', total)
+  process.exit(1)
+}
+
+if (statements.pct < minStatementPercentage) {
+  console.log('🚨 Statement coverage %d is below minimum %d%%', statements.pct, minStatementPercentage)
+  console.log('file %s', coverageFilename)
+  process.exit(1)
+}
+
+console.log(
+  '✅ Total statement coverage %d%% is >= minimum %d%%',
+  statements.pct, minStatementPercentage
+)

coverage/coverage-summary.json

@@ -0,0 +1,4 @@
+{"total": {"lines":{"total":3,"covered":3,"skipped":0,"pct":100},"statements":{"total":3,"covered":3,"skipped":0,"pct":100},"functions":{"total":1,"covered":1,"skipped":0,"pct":100},"branches":{"total":0,"covered":0,"skipped":0,"pct":100}}
+,"/Users/gleb/git/instrument-example/src/App.js": {"lines":{"total":1,"covered":1,"skipped":0,"pct":100},"functions":{"total":1,"covered":1,"skipped":0,"pct":100},"statements":{"total":1,"covered":1,"skipped":0,"pct":100},"branches":{"total":0,"covered":0,"skipped":0,"pct":100}}
+,"/Users/gleb/git/instrument-example/src/index.js": {"lines":{"total":2,"covered":2,"skipped":0,"pct":100},"functions":{"total":0,"covered":0,"skipped":0,"pct":100},"statements":{"total":2,"covered":2,"skipped":0,"pct":100},"branches":{"total":0,"covered":0,"skipped":0,"pct":100}}
+}

package.json

@@ -5,7 +5,8 @@
   "main": "index.js",
   "bin": {
     "check-coverage": "bin/check-coverage.js",
-    "only-covered": "bin/only-covered.js"
+    "only-covered": "bin/only-covered.js",
+    "check-total": "bin/check-total.js"
   },
   "files": [
     "bin"