Retain pure annotations in class fields (#3599)

* Retain pure annotations in class fields * Improve coverage * Only check key if it is computed
rollup · May 27, 2020 · e2a85a1 · e2a85a1
1 parent 9bff788
commit e2a85a1
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diff --git a/src/utils/pureComments.ts b/src/utils/pureComments.ts
@@ -3,6 +3,16 @@ import * as acorn from 'acorn';
 import { base as basicWalker } from 'acorn-walk';
 import { CommentDescription } from '../Module';
 
+// patch up acorn-walk until class-fields are officially supported
+basicWalker.FieldDefinition = function (node: any, st: any, c: any) {
+	if (node.computed) {
+		c(node.key, st, 'Expression');
+	}
+	if (node.value) {
+		c(node.value, st, 'Expression');
+	}
+};
+
 function handlePureAnnotationsOfNode(
 	node: acorn.Node,
 	state: { commentIndex: number; commentNodes: CommentDescription[] },

diff --git a/test/form/samples/pure-class-field/_config.js b/test/form/samples/pure-class-field/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'retains pure annotations in class fields'
+};
diff --git a/test/form/samples/pure-class-field/_expected.js b/test/form/samples/pure-class-field/_expected.js
@@ -0,0 +1,6 @@
+class main {
+	static k = /*#__PURE__*/ V();
+	static [/*#__PURE__*/ W()];
+}
+
+export default main;
diff --git a/test/form/samples/pure-class-field/main.js b/test/form/samples/pure-class-field/main.js
@@ -0,0 +1,4 @@
+export default class {
+	static k = /*#__PURE__*/ V();
+	static [/*#__PURE__*/ W()];
+}