feat: allow any JS identifier in define, not ASCII-only

docs/config/index.md

@@ -123,11 +123,11 @@ export default defineConfig(async ({ command, mode }) => {
 
   Define global constant replacements. Entries will be defined as globals during dev and statically replaced during build.
 
-  - Starting from `2.0.0-beta.70`, string values will be used as raw expressions, so if defining a string constant, it needs to be explicitly quoted (e.g. with `JSON.stringify`).
-
-  - Replacements are performed only when the match is surrounded by word boundaries (`\b`).
+  :::warning String constants
+  Starting from `2.0.0-beta.70`, string values will be used as raw expressions, so if defining a string constant, it needs to be explicitly quoted (e.g. with `JSON.stringify`).
+  :::
 
-  Because it's implemented as straightforward text replacements without any syntax analysis, we recommend using `define` for CONSTANTS only.
+  Because it's implemented as straightforward [RegExp-based](https://github.com/vitejs/vite/blob/main/packages/vite/src/node/plugins/define.ts#L62-L76) text replacements without any syntax analysis, we recommend using `define` for CONSTANTS only.
 
   For example, `process.env.FOO` and `__APP_VERSION__` are good fits. But `process` or `global` should not be put into this option. Variables can be shimmed or polyfilled instead.
 

packages/playground/define/__tests__/define.spec.ts

@@ -20,4 +20,12 @@ test('string', async () => {
   expect(await page.textContent('.spread-array')).toBe(
     JSON.stringify([...defines.__STRING__])
   )
+  expect(await page.textContent('.dollar-identifier')).toBe(
+    String(defines.$DOLLAR)
+  )
+  expect(await page.textContent('.unicode-identifier')).toBe(
+    String(defines.ÖUNICODE_LETTERɵ)
+  )
+  expect(await page.textContent('.no-identifier-substring')).toBe(String(true))
+  expect(await page.textContent('.no-property')).toBe(String(true))
 })

packages/playground/define/index.html

@@ -9,6 +9,10 @@ <h1>Define</h1>
 <p>process as property: <code class="process-as-property"></code></p>
 <p>spread object: <code class="spread-object"></code></p>
 <p>spread array: <code class="spread-array"></code></p>
+<p>dollar identifier: <code class="dollar-identifier"></code></p>
+<p>unicode identifier: <code class="unicode-identifier"></code></p>
+<p>no property: <code class="no-property"></code></p>
+<p>no identifier substring: <span class="no-identifier-substring"></span></p>
 
 <script type="module">
   text('.exp', __EXP__)
@@ -25,6 +29,15 @@ <h1>Define</h1>
     })
   )
   text('.spread-array', JSON.stringify([...`"${__STRING__}"`]))
+  text('.dollar-identifier', $DOLLAR)
+  text('.unicode-identifier', ÖUNICODE_LETTERɵ)
+
+  // make sure these kinds of use are NOT replaced:
+  const obj = { [`${'_'}_EXP__`]: true }
+  text('.no-property', obj.__EXP__)
+
+  window[`${'_'}_EXP__SUBSTR__`] = true
+  text('.no-identifier-substring', __EXP__SUBSTR__)
 
   function text(el, text) {
     document.querySelector(el).textContent = text

packages/playground/define/vite.config.js

@@ -15,6 +15,8 @@ module.exports = {
         }
       }
     },
-    'process.env.SOMEVAR': '"SOMEVAR"'
+    'process.env.SOMEVAR': '"SOMEVAR"',
+    $DOLLAR: 456,
+    ÖUNICODE_LETTERɵ: 789
   }
 }

packages/vite/src/node/plugins/define.ts

@@ -61,14 +61,18 @@ export function definePlugin(config: ResolvedConfig): Plugin {
 
     const pattern = new RegExp(
       // Do not allow preceding '.', but do allow preceding '...' for spread operations
-      '(?<!(?<!\\.\\.)\\.)\\b(' +
+      '(?<!(?<!\\.\\.)\\.)' +
+        // Must follow beginning of a line or a char that can't be part of an identifier
+        '(?<=^|[^\\p{L}\\p{N}_$])(' +
         Object.keys(replacements)
           .map((str) => {
             return str.replace(/[-[\]/{}()*+?.\\^$|]/g, '\\$&')
           })
           .join('|') +
-        ')\\b',
-      'g'
+        // Must be followed by: end of a line, a char that can't be part of an identifier or
+        // anything following a dot (handles cases where replacement includes a trailing dot)
+        ')(?=$|[^\\p{L}\\p{N}_$]|(?<=\\.).)',
+      'gu'
     )
 
     return [replacements, pattern]