deps: Remove unmaintained dependency: disparity (#1264)

* Remove unmaintained dependency: disparity

The dependency disparity has not been updated for 4 years and is using
a very old version of the diff package which has a security alert.

This alert is not relevant to the current usage of the package, however
it does generate noise when installing. Additionally, it seems unwise to
be relying on unmaintained packages.

This commit replaces disparity with diff and adds some code to color the
output which is based on disparity's logic.

* Use chalk to color diff output instead of ansi-styles

Author: ben-turner

package.json

@@ -37,7 +37,7 @@
     "chalk": "^2.3.0",
     "chokidar": "^2.0.4",
     "concat-stream": "^1.6.0",
-    "disparity": "^2.0.0",
+    "diff": "^4.0.1",
     "doctrine-temporary-fork": "2.1.0",
     "get-port": "^4.0.0",
     "git-url-parse": "^10.0.1",

src/commands/readme.js

@@ -5,7 +5,7 @@ const documentation = require('../');
 const sharedOptions = require('./shared_options');
 const inject = require('mdast-util-inject');
 const chalk = require('chalk');
-const disparity = require('disparity');
+const diff = require('diff');
 const getReadmeFile = require('../get-readme-file');
 
 module.exports.command = 'readme [input..]';
@@ -94,22 +94,48 @@ module.exports.handler = function readme(argv) {
         .process(readmeContent)
     )
     .then(file => {
-      const diffOutput = disparity.unified(readmeContent, file.contents, {
-        paths: [argv.readmeFile, argv.readmeFile]
-      });
-      if (!diffOutput.length) {
+      const diffRaw = diff.createPatch(
+        '',
+        readmeContent,
+        file.contents,
+        '',
+        ''
+      );
+      if (!diffRaw.length) {
         log(`${argv.readmeFile} is up to date.`);
         process.exit(0);
       }
 
+      // Replace diff headers with real values
+      const cleanedDiff = diffRaw
+        .replace(/^([^\n]+)\n([^\n]+)\n/m, '')
+        .replace(/^---.*/gm, `--- ${argv.readmeFile}\tremoved`)
+        .replace(/^\+\+\+.*/gm, `+++ ${argv.readmeFile}\tadded`);
+
+      // Includes newlines for easier joins
+      const diffLines = cleanedDiff.split(/^/m);
+      const diffHeader = diffLines
+        .slice(0, 2)
+        .join('')
+        .replace(/[^\n\r]+/g, chalk.yellow('$&'));
+      const diffBody = diffLines
+        .slice(2)
+        .join('')
+        .replace(/^-[^\n\r]*/gm, chalk.red('$&'))
+        .replace(/^\+[^\n\r]*/gm, chalk.green('$&'))
+        .replace(/^@@.+@@/gm, chalk.magenta('$&'));
+
       if (argv.d) {
         log(
           chalk.bold(`${argv.readmeFile} needs the following updates:`),
-          `\n${diffOutput}`
+          `\n${diffHeader}${diffBody}`
         );
         process.exit(1);
       } else {
-        log(chalk.bold(`Updating ${argv.readmeFile}`), `\n${diffOutput}`);
+        log(
+          chalk.bold(`Updating ${argv.readmeFile}`),
+          `\n${diffHeader}${diffBody}`
+        );
       }
 
       fs.writeFileSync(argv.readmeFile, file.contents);

yarn.lock

@@ -930,7 +930,7 @@ ansi-regex@^4.1.0:
   resolved "https://registry.yarnpkg.com/ansi-regex/-/ansi-regex-4.1.0.tgz#8b9f8f08cf1acb843756a839ca8c7e3168c51997"
   integrity sha512-1apePfXM1UOSqw0o9IiFAovVz9M5S1Dg+4TrDwfMewQ6p/rmMueb7tWZjQ1rx4Loy1ArBggoqGpfqqdI4rondg==
 
-ansi-styles@^2.0.1, ansi-styles@^2.2.1:
+ansi-styles@^2.2.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/ansi-styles/-/ansi-styles-2.2.1.tgz#b432dd3358b634cf75e1e4664368240533c1ddbe"
 
@@ -2070,20 +2070,14 @@ detective@^4.0.0:
     acorn "^5.2.1"
     defined "^1.0.0"
 
-diff@^1.3.2:
-  version "1.4.0"
-  resolved "https://registry.yarnpkg.com/diff/-/diff-1.4.0.tgz#7f28d2eb9ee7b15a97efd89ce63dcfdaa3ccbabf"
-
 diff@^3.2.0:
   version "3.5.0"
   resolved "https://registry.yarnpkg.com/diff/-/diff-3.5.0.tgz#800c0dd1e0a8bfbc95835c202ad220fe317e5a12"
 
-disparity@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/disparity/-/disparity-2.0.0.tgz#57ddacb47324ae5f58d2cc0da886db4ce9eeb718"
-  dependencies:
-    ansi-styles "^2.0.1"
-    diff "^1.3.2"
+diff@^4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/diff/-/diff-4.0.1.tgz#0c667cb467ebbb5cea7f14f135cc2dba7780a8ff"
+  integrity sha512-s2+XdvhPCOF01LRQBC8hf4vhbVmI2CGS5aZnxLJlT5FtdhPCDFq80q++zK2KlrVorVDdL5BOGZ/VfLrVtYNF+Q==
 
 [email protected]:
   version "2.1.0"