feat(core): expose mergeConfigs utility

packages/core/src/config.ts

@@ -164,3 +164,32 @@ export function resolveConfig<Theme extends {} = {}>(
 
   return resolved
 }
+
+/**
+ * Merge multiple configs into one, later ones have higher priority
+ */
+export function mergeConfigs<Theme extends {} = {}>(
+  configs: UserConfig<Theme>[],
+): UserConfig<Theme> {
+  function getMerged<T extends 'rules' | 'variants' | 'extractors' | 'shortcuts' | 'preflights' | 'preprocess' | 'postprocess' | 'extendTheme' | 'safelist' | 'separators' | 'presets'>(key: T): ToArray<Required<UserConfig<Theme>>[T]> {
+    return uniq(configs.flatMap(p => toArray(p[key] || []) as any[])) as any
+  }
+
+  const merged = Object.assign(
+    {},
+    ...configs,
+    {
+      presets: getMerged('presets'),
+      safelist: getMerged('safelist'),
+      preprocess: getMerged('preprocess'),
+      postprocess: getMerged('postprocess'),
+      preflights: getMerged('preflights'),
+      rules: getMerged('rules'),
+      variants: getMerged('variants'),
+      shortcuts: getMerged('shortcuts'),
+      extractors: getMerged('extractors'),
+    },
+  )
+
+  return merged
+}

packages/core/src/index.ts

@@ -2,3 +2,4 @@ export * from './types'
 export * from './utils'
 export * from './extractors'
 export * from './generator'
+export * from './config'

test/config.test.ts

@@ -1,8 +1,8 @@
 import type { Preset, UserConfig } from '@unocss/core'
-import { createGenerator } from '@unocss/core'
+import { createGenerator, mergeConfigs } from '@unocss/core'
 import type { Theme } from '@unocss/preset-mini'
 import presetMini from '@unocss/preset-mini'
-import { describe, expect, test } from 'vitest'
+import { describe, expect, it, test } from 'vitest'
 
 describe('config', () => {
   const createUno = (userConfig: UserConfig) => {
@@ -133,3 +133,47 @@ describe('config', () => {
     `)
   })
 })
+
+describe('mergeConfigs', () => {
+  it('basic', () => {
+    expect(mergeConfigs([
+      {
+        shortcuts: {
+          foo: 'string',
+        },
+      },
+      {
+        shortcuts: [
+          {
+            bar: 'string',
+          },
+          [/a/i, () => 'a'],
+        ],
+      },
+    ]))
+      .toMatchInlineSnapshot(`
+        {
+          "extractors": [],
+          "postprocess": [],
+          "preflights": [],
+          "preprocess": [],
+          "presets": [],
+          "rules": [],
+          "safelist": [],
+          "shortcuts": [
+            {
+              "foo": "string",
+            },
+            {
+              "bar": "string",
+            },
+            [
+              /a/i,
+              [Function],
+            ],
+          ],
+          "variants": [],
+        }
+      `)
+  })
+})