fix(loader): support type assertion

src/loader/babel.ts

@@ -31,8 +31,12 @@ const babelPluginUntyped: PluginItem = function (api: ConfigAPI) {
               .map(c => c.value)
           )
 
-          if (p.node.value.type === 'ObjectExpression') {
-            const schemaProp = p.node.value.properties.find(prop =>
+          const valueNode = (p.node.value.type === 'TSTypeAssertion' || p.node.value.type === 'TSAsExpression')
+            ? p.node.value.expression
+            : p.node.value
+
+          if (valueNode.type === 'ObjectExpression') {
+            const schemaProp = valueNode.properties.find(prop =>
               ('key' in prop) && prop.key.type === 'Identifier' && prop.key.name === '$schema'
             )
             if (schemaProp && 'value' in schemaProp) {
@@ -45,12 +49,12 @@ const babelPluginUntyped: PluginItem = function (api: ConfigAPI) {
               }
             } else {
               // Object has not $schema
-              p.node.value.properties.unshift(...astify({ $schema: schema }).properties)
+              valueNode.properties.unshift(...astify({ $schema: schema }).properties)
             }
           } else {
             // Literal value
             p.node.value = t.objectExpression([
-              t.objectProperty(t.identifier('$default'), p.node.value),
+              t.objectProperty(t.identifier('$default'), valueNode),
               t.objectProperty(t.identifier('$schema'), astify(schema))
             ])
           }

test/transform.test.ts

@@ -309,10 +309,80 @@ describe('transform (jsdoc)', () => {
       }
     })
   })
+
+  it('correctly parses type assertion', () => {
+    const result = transform(`
+      import type { InputObject } from 'untyped'
+      export default {
+        /**
+         * @typedef {'src' | 'root'} HumanReadable
+         * @type {Array<HumanReadable>}
+         */
+        srcDir: <InputObject>{
+          $resolve(val, get) {
+            return val ?? 'src'
+          }
+        }
+      }
+    `)
+    expect(result).toMatchInlineSnapshot(`
+      "export default {
+        srcDir: {
+          $schema: {
+            title: \\"\\",
+            description: \\"\\",
+            tags: [],
+            tsType: \\"Array<'src' | 'root'>\\",
+            markdownType: \\"Array<HumanReadable>\\"
+          },
+
+          $resolve(val, get) {
+            return val ?? 'src';
+          }
+
+        }
+      };"
+    `)
+  })
+
+  it('correctly parses type as assertion', () => {
+    const result = transform(`
+      import type { InputObject } from 'untyped'
+      export default {
+        /**
+         * @typedef {'src' | 'root'} HumanReadable
+         * @type {Array<HumanReadable>}
+         */
+        srcDir: {
+          $resolve(val, get) {
+            return val ?? 'src'
+          }
+        } as InputObject
+      }
+    `)
+    expect(result).toMatchInlineSnapshot(`
+      "export default {
+        srcDir: {
+          $schema: {
+            title: \\"\\",
+            description: \\"\\",
+            tags: [],
+            tsType: \\"Array<'src' | 'root'>\\",
+            markdownType: \\"Array<HumanReadable>\\"
+          },
+
+          $resolve(val, get) {
+            return val ?? 'src';
+          }
+
+        }
+      };"
+    `)
+  })
 })
 
 function expectCodeToMatch (code: string, pattern: RegExp, expected: any) {
-  const [, result] = code.match(pattern)
+  const [, result] = code.match(pattern) || []
   expect(result).toBeDefined()
   // eslint-disable-next-line
   const obj = Function('"use strict";return (' + result.replace(/;$/, '') + ')')()