feat: merge npmrc files

Closes #258

.npmrc

@@ -1,3 +1,4 @@
 ; This file is automatically added by @npmcli/template-oss. Do not edit.
 
 package-lock=false
+install-links=false

lib/util/parser.js

@@ -5,6 +5,7 @@ const NpmPackageJson = require('@npmcli/package-json')
 const jsonParse = require('json-parse-even-better-errors')
 const Diff = require('diff')
 const { unset } = require('lodash')
+const ini = require('ini')
 const template = require('./template.js')
 const jsonDiff = require('./json-diff')
 const merge = require('./merge.js')
@@ -176,9 +177,33 @@ class Js extends Base {
 }
 
 class Ini extends Base {
-  // XXX: add merge mode for updating ini files
-  static types = ['npmrc']
+  static types = ['ini']
   comment = (c) => `; ${c}`
+
+  toString (s) {
+    return typeof s === 'string' ? s : ini.stringify(s)
+  }
+
+  parse (s) {
+    return typeof s === 'string' ? ini.parse(s) : s
+  }
+
+  prepare (s, t) {
+    let source = s
+    if (typeof this.merge === 'function' && t) {
+      source = this.merge(t, s)
+    }
+    return super.prepare(this.toString(source))
+  }
+
+  diff (t, s) {
+    return jsonDiff(this.parse(t), this.parse(s), this.DELETE)
+  }
+}
+
+class IniMerge extends Ini {
+  static types = ['npmrc']
+  merge = (t, s) => merge(t, s)
 }
 
 class Markdown extends Base {
@@ -314,6 +339,7 @@ const Parsers = {
   Gitignore,
   Js,
   Ini,
+  IniMerge,
   Markdown,
   Yml,
   YmlMerge,

package.json

@@ -45,6 +45,7 @@
     "glob": "^8.0.1",
     "handlebars": "^4.7.7",
     "hosted-git-info": "^6.0.0",
+    "ini": "^3.0.1",
     "json-parse-even-better-errors": "^3.0.0",
     "just-deep-map-values": "^1.1.1",
     "just-diff": "^5.0.1",