feat: insert code coverage badge if not found (#11)

Author: bahmutov

README.md

@@ -1,4 +1,4 @@
-# check-code-coverage [![ci status][ci image]][ci url] ![mock coverage](https://img.shields.io/badge/code--coverage-100%-brightgreen)
+# check-code-coverage [![ci status][ci image]][ci url] ![check-code-coverage](https://img.shields.io/badge/code--coverage-100%-brightgreen)
 > Utilities for checking the coverage produced by NYC against extra or missing files
 
 ## Use
@@ -34,7 +34,7 @@ check-total --from coverage/coverage-summary.json --min 80
 
 If your README.md includes Shields.io badge, like this
 
-    ![code coverage](https://img.shields.io/badge/code--coverage-80%-brightgreen)
+    ![check-code-coverage](https://img.shields.io/badge/code--coverage-80%-brightgreen)
 
 You can update it using statements covered percentage from `coverage/coverage-summary.json` by running
 
@@ -44,12 +44,14 @@ update-badge
 
 If the coverage summary has 96%, then the above badge would be updated to
 
-    ![code coverage](https://img.shields.io/badge/code--coverage-96%-brightgreen)
+    ![check-code-coverage](https://img.shields.io/badge/code--coverage-96%-brightgreen)
 
 Related project: [dependency-version-badge](https://github.com/bahmutov/dependency-version-badge)
 
 The badges will have different colors, depending on the coverage, see [bin/update-badge.js](bin/update-badge.js)
 
+If the code coverage badge is not found, a new badge is inserted on the first line.
+
 ## Debug
 
 To see verbose log messages, run with `DEBUG=check-code-coverage` environment variable

bin/update-badge.js

@@ -4,6 +4,7 @@
 const debug = require('debug')('check-code-coverage')
 const path = require('path')
 const fs = require('fs')
+const os = require('os')
 
 const availableColors = ['red', 'yellow', 'green', 'brightgreen']
 
@@ -47,13 +48,31 @@ function updateBadge() {
     debug('coverage regex: "%s"', coverageRe)
     debug('new coverage badge: "%s"', coverageBadge)
 
-    const updatedReadmeText = readmeText.replace(
+    let found
+    let updatedReadmeText = readmeText.replace(
       coverageRe,
       (match) => {
+        found = true
         debug('match: %o', match)
         return coverageBadge
       },
     )
+
+    if (!found) {
+      console.log('⚠️ Could not find code coverage badge in file %s', readmeFilename)
+      console.log('Insert new badge on the first line')
+      // use NPM package name as label to flag where this badge is coming from
+      const badge = `![check-code-coverage](${coverageBadge})`
+      debug('inserting new badge: %s', badge)
+
+      const lines = readmeText.split(os.EOL)
+      if (lines.length < 1) {
+        console.error('File %s has no lines, cannot insert code coverage badge', readmeFilename)
+        return readmeText
+      }
+      lines[0] += ' ' + badge
+      updatedReadmeText = lines.join(os.EOL)
+    }
     return updatedReadmeText
   }