diff --git a/src/main/ts/envapi.ts b/src/main/ts/envapi.ts
index e2010b6..5d1d099 100644
--- a/src/main/ts/envapi.ts
+++ b/src/main/ts/envapi.ts
@@ -91,6 +91,8 @@ export const loadSafe = (...files: string[]): NodeJS.ProcessEnv =>
     ...files
   )
 
-export const config = (def = DOTENV, ...files: string[]): NodeJS.ProcessEnv =>
-  Object.assign(process.env, loadSafe(def, ...files))
+export const populate = (env: NodeJS.ProcessEnv, extra?: NodeJS.ProcessEnv): NodeJS.ProcessEnv =>
+  Object.assign(env, extra)
 
+export const config = (def = DOTENV, ...files: string[]): NodeJS.ProcessEnv =>
+  populate(process.env, loadSafe(def, ...files))
diff --git a/src/test/ts/index.test.ts b/src/test/ts/index.test.ts
index 380ff01..8c4f4ff 100644
--- a/src/test/ts/index.test.ts
+++ b/src/test/ts/index.test.ts
@@ -3,7 +3,7 @@ import fs from 'node:fs'
 import os from 'node:os'
 import path from 'node:path'
 import { describe, test, afterAll } from 'vitest'
-import { parse, stringify, load, loadSafe, config } from '../../main/ts/index.js'
+import { parse, stringify, load, loadSafe, populate, config } from '../../main/ts/index.js'
 
 const randomId= () => Math.random().toString(36).slice(2)
 const tempdir = (prefix: string = `temp-${randomId()}`): string => {
@@ -126,4 +126,10 @@ JSONSTR='{"foo": "b a r"}'`
       delete process.env.ENV1
     })
   })
+
+  describe('populate()', () => {
+    test('populates env', () => {
+      assert.deepEqual(populate({FOO: 'BAR'}, { FOO: 'BAZ' }), { FOO: 'BAZ' })
+    })
+  })
 })