From d2e2d488bf2dea68bbf7e90a2491d857dfe62fb7 Mon Sep 17 00:00:00 2001
From: Ben Shaw <ben@beneboy.co.nz>
Date: Sat, 31 Aug 2019 14:56:03 +1200
Subject: [PATCH] feat(JS): Added checking for empty string semaphore in
 imports

---
 py/tests/test_document_compiler.py |  2 +-
 ts/interpreter.ts                  | 23 ++++++++++++++++++++++-
 ts/parsing.test.ts                 | 30 ++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/py/tests/test_document_compiler.py b/py/tests/test_document_compiler.py
index 78eced7d9c..d245507165 100644
--- a/py/tests/test_document_compiler.py
+++ b/py/tests/test_document_compiler.py
@@ -111,7 +111,7 @@ def test_compile_article():
 
 def test_import_appending():
     """Found imports in a piece of code should be added to the list of imports the code chunk already specifies."""
-    c = CodeChunk('import moda\nimport modb', imports=['modc', 'modd'], language='python')
+    c = CodeChunk('import moda\nimport modb\nimport modc', imports=['modc', 'modd'], language='python')
 
     dc = DocumentCompiler()
     dc.compile(c)
diff --git a/ts/interpreter.ts b/ts/interpreter.ts
index c9cb30e6be..2850f098bb 100644
--- a/ts/interpreter.ts
+++ b/ts/interpreter.ts
@@ -123,6 +123,27 @@ export function execute(
   })
 }
 
+/**
+ * Add `imports` to the `CodeChunk.imports` array if they aren't already there. If the existing imports array contains
+ * the empty string semaphore then no more imports should be added.
+ */
+function setCodeChunkImports(code: CodeChunk, imports: string[]): void {
+  if (code.imports === undefined) {
+    code.imports = imports
+    return
+  }
+
+  if (code.imports.includes('')) return
+
+  // Can't do any kind of de-dupe magic as code.imports might contain types other than strings.
+  imports.forEach(im => {
+    // Typescript seems to forget that this has already been checked to not be undefined
+    if (code.imports === undefined) return
+
+    if (!code.imports.includes(im)) code.imports.push(im)
+  })
+}
+
 /**
  * Traverse a `Node` hierarchy and push any `Parameter` that is found onto the `parameters` array,
  * and any executable code block onto the `code` array.
@@ -146,7 +167,7 @@ export function parseItem(
       if (isA('CodeChunk', item)) {
         const parseResult = parseCodeChunk(item)
 
-        item.imports = parseResult.imports
+        setCodeChunkImports(item, parseResult.imports)
         item.declares = parseResult.declares
         item.assigns = parseResult.assigns
         item.alters = parseResult.alters
diff --git a/ts/parsing.test.ts b/ts/parsing.test.ts
index e643c25e64..9e042a67b2 100644
--- a/ts/parsing.test.ts
+++ b/ts/parsing.test.ts
@@ -348,6 +348,36 @@ describe('Parsing information from an Article', () => {
       'IntegerSchema'
     )
   })
+
+  test('it adds imports it finds to existing CodeChunk imports', () => {
+    const c = codeChunk(
+      "import { export1 } from 'module-name3'\nimport { export2 } from 'module-name4'",
+      {
+        language: 'javascript',
+        imports: ['module-name1', 'module-name2', 'module-name3']
+      }
+    )
+    parseItem(c, [], [])
+
+    expect(c.imports).toHaveLength(4)
+    expect(c.imports).toContain('module-name1')
+    expect(c.imports).toContain('module-name2')
+    expect(c.imports).toContain('module-name3')
+    expect(c.imports).toContain('module-name4')
+  })
+
+  test("it doesn't add imports it finds to existing CodeChunk imports if the empty string semaphore is present", () => {
+    const c = codeChunk(
+      "import { export1 } from 'module-name3'\nimport { export2 } from 'module-name4'",
+      { language: 'javascript', imports: ['module-name1', 'module-name2', ''] }
+    )
+    parseItem(c, [], [])
+
+    expect(c.imports).toHaveLength(3)
+    expect(c.imports).toContain('module-name1')
+    expect(c.imports).toContain('module-name2')
+    expect(c.imports).toContain('')
+  })
 })
 
 describe('CLI parameter parsing', () => {