fix: inline color selector in libnpmdiff

Eventually we'll use npm to do this so we don't have to check if color
is enabled

Author: wraithgar

workspaces/libnpmdiff/lib/format-diff.js

@@ -1,8 +1,24 @@
-const colorizeDiff = require('@npmcli/disparity-colors')
 const jsDiff = require('diff')
 
 const shouldPrintPatch = require('./should-print-patch.js')
 
+const colors = {
+  // red
+  removed: { open: '\x1B[31m', close: '\x1B[39m' },
+  // green
+  added: { open: '\x1B[32m', close: '\x1B[39m' },
+  // blue
+  header: { open: '\x1B[34m', close: '\x1B[39m' },
+  // cyan
+  section: { open: '\x1B[36m', close: '\x1B[39m' },
+}
+
+const color = (colorStr, colorId) => {
+  const { open, close } = colors[colorId]
+  // avoid highlighting the "\n" (would highlight till the end of the line)
+  return colorStr.replace(/[^\n\r]+/g, open + '$&' + close)
+}
+
 const formatDiff = ({ files, opts = {}, refs, versions }) => {
   let res = ''
   const srcPrefix = opts.diffNoPrefix ? '' : opts.diffSrcPrefix || 'a/'
@@ -83,9 +99,17 @@ const formatDiff = ({ files, opts = {}, refs, versions }) => {
       header(`+++ ${names.b}`)
     }
 
-    res += (opts.color
-      ? colorizeDiff(patch, { headerLength })
-      : patch)
+    if (opts.color) {
+      // this RegExp will include all the `\n` chars into the lines, easier to join
+      const lines = patch.split(/^/m)
+      res += color(lines.slice(0, headerLength).join(''), 'header')
+      res += lines.slice(headerLength).join('')
+        .replace(/^-.*/gm, color('$&', 'removed'))
+        .replace(/^\+.*/gm, color('$&', 'added'))
+        .replace(/^@@.+@@/gm, color('$&', 'section'))
+    } else {
+      res += patch
+    }
   }
 
   return res.trim()

workspaces/libnpmdiff/tap-snapshots/test/format-diff.js.test.cjs

@@ -33,11 +33,11 @@ index v1.0.0..v2.0.0
 `
 
 exports[`test/format-diff.js TAP colored output > should output expected colored diff result 1`] = `
-[33mdiff --git a/foo.js b/foo.js[39m
-[33mindex v1.0.0..v2.0.0 100644[39m
-[33m--- a/foo.js[39m
-[33m+++ b/foo.js[39m
-[35m@@ -1,2 +1,2 @@[39m
+[34mdiff --git a/foo.js b/foo.js[39m
+[34mindex v1.0.0..v2.0.0 100644[39m
+[34m--- a/foo.js[39m
+[34m+++ b/foo.js[39m
+[36m@@ -1,2 +1,2 @@[39m
  "use strict"
 -module.exports = "foo"
 +module.exports = "foobar"