feature: putout: ignore: add ability to merge negated (kaelzhang/node…

…-ignore#107)

packages/putout/lib/merge.js

@@ -1,11 +1,39 @@
 'use strict';
 
 const deepmerge = require('deepmerge');
-const arrayUnion = (...a) => [...new Set(a.flat())];
+
+const isString = (a) => typeof a === 'string';
+const arrayUnion = (...a) => {
+    const flatten = a.flat();
+    return mergeIgnore(Array.from(new Set(flatten)));
+};
+
 const arrayMerge = (a, b) => arrayUnion(b, a);
 
 module.exports = (...args) => {
     return deepmerge.all(args, {
         arrayMerge,
     });
 };
+
+function mergeIgnore(list) {
+    const negatives = [];
+
+    for (const current of list) {
+        if (isString(current) && current.startsWith('!'))
+            negatives.push(current.slice(1));
+    }
+
+    for (const current of negatives) {
+        const index = list.indexOf(current);
+
+        if (index >= 0) {
+            list.splice(index, 1);
+
+            const negIndex = list.indexOf(`!${current}`);
+            list.splice(negIndex, 1);
+        }
+    }
+
+    return list;
+}

packages/putout/lib/merge.spec.js

@@ -22,3 +22,39 @@ test('putout: merge', (t) => {
     t.deepEqual(result, expected);
     t.end();
 });
+
+test('putout: merge: ignore', (t) => {
+    const defaultConfig = {
+        plugins: ['remove-unused-variables'],
+    };
+
+    const result = merge(defaultConfig, {
+        ignore: [
+            '**/coverage',
+            '!**/coverage',
+        ],
+    });
+
+    const expected = {
+        plugins: ['remove-unused-variables'],
+        ignore: [],
+    };
+
+    t.deepEqual(result, expected);
+    t.end();
+});
+
+test('putout: merge: rules', (t) => {
+    const options = {
+        rules: {
+            'filesystem/remove-files': ['on', {
+                names: ['*.md'],
+            }],
+        },
+    };
+
+    const result = merge({}, options);
+
+    t.deepEqual(result, options);
+    t.end();
+});