improve export capture logic

Author: rmorshea

src/idom/web/utils.py

@@ -50,15 +50,46 @@ def resolve_module_exports_from_url(url: str, max_depth: int) -> Set[str]:
 
 def resolve_module_exports_from_source(content: str) -> Tuple[Set[str], Set[str]]:
     names: Set[str] = set()
-    for match in _JS_MODULE_EXPORT_PATTERN.findall(content):
-        for export in match.split(","):
-            export_parts = export.split(" as ", 1)
-            names.add(export_parts[-1].strip())
-    names.update(_JS_MODULE_EXPORT_FUNC_PATTERN.findall(content))
-    names.update(_JS_MODULE_EXPORT_NAME_PATTERN.findall(content))
-
-    references: Set[str] = set(_JS_MODULE_EXPORT_FROM_REF_PATTERN.findall(content))
-    return names, references
+    references: Set[str] = set()
+    for export in _JS_EXPORT_PATTERN.findall(
+        # strip comments
+        _JS_LINE_COMMENT.sub("", content)
+    ):
+        export = export.rstrip(";").strip()
+        # Exporting individual features
+        if export.startswith("let "):
+            names.update(let.split("=", 1)[0] for let in export[4:].split(","))
+        elif export.startswith("function "):
+            names.add(export[9:].split("(", 1)[0])
+        elif export.startswith("class "):
+            names.add(export[6:].split("{", 1)[0])
+        # Renaming exports and export list
+        elif export.startswith("{") and export.endswith("}"):
+            names.update(
+                item.split(" as ", 1)[-1] for item in export.strip("{}").split(",")
+            )
+        # Exporting destructured assignments with renaming
+        elif export.startswith("const "):
+            names.update(
+                item.split(":", 1)[0]
+                for item in export[6:].split("=", 1)[0].strip("{}").split(",")
+            )
+        # Default exports
+        elif export.startswith("default "):
+            names.add("default")
+        # Aggregating modules
+        elif export.startswith("* as "):
+            names.add(export[5:].split(" from ", 1)[0])
+        elif export.startswith("* "):
+            references.add(export[2:].split("from ", 1)[-1].strip("'\""))
+        elif export.startswith("{") and " from " in export:
+            names.update(
+                item.split(" as ", 1)[-1]
+                for item in export.split(" from ")[0].strip("{}").split(",")
+            )
+        else:
+            logger.warning(f"Unknown export type {export!r}")
+    return {n.strip() for n in names}, {r.strip() for r in references}
 
 
 def _resolve_relative_file_path(base_path: Path, rel_url: str) -> Path:
@@ -81,16 +112,5 @@ def _resolve_relative_url(base_url: str, rel_url: str) -> str:
     return f"{base_url}/{rel_url}"
 
 
-_JS_MODULE_EXPORT_PATTERN = re.compile(
-    r";?\s*export\s*{([0-9a-zA-Z_$\s,]*)}\s*;", re.MULTILINE
-)
-_JS_VAR = r"[a-zA-Z_$][0-9a-zA-Z_$]*"
-_JS_MODULE_EXPORT_NAME_PATTERN = re.compile(
-    fr";?\s*export\s+({_JS_VAR})\s+{_JS_VAR}\s*;", re.MULTILINE
-)
-_JS_MODULE_EXPORT_FUNC_PATTERN = re.compile(
-    fr";?\s*export\s+function\s+({_JS_VAR})\s*\(.*?", re.MULTILINE
-)
-_JS_MODULE_EXPORT_FROM_REF_PATTERN = re.compile(
-    r""";?\s*export\s+\*\s+from\s+['"](.*?)['"];"""
-)
+_JS_LINE_COMMENT = re.compile(r"//.*$")
+_JS_EXPORT_PATTERN = re.compile(r";?\s*export(?=\s+|{)(.*?(?:;|}\s*))", re.MULTILINE)

tests/test_web/js_fixtures/exports_syntax.js

@@ -0,0 +1,23 @@
+// Copied from: https://developer.mozilla.org/en-US/docs/web/javascript/reference/statements/export
+
+// Exporting individual features
+export let name1, name2, name3; // also var, const
+export let name4 = 4, name5 = 5, name6; // also var, const
+export function functionName(){...}
+export class ClassName {...}
+
+// Export list
+export { name7, name8, name9 };
+
+// Renaming exports
+export { variable1 as name10, variable2 as name11, name12 };
+
+// Exporting destructured assignments with renaming
+export const { name13, name14: bar } = o;
+
+// Aggregating modules
+export * from "source1"; // does not set the default export
+export * from "source2"; // does not set the default export
+export * as name15 from "source3"; // Draft ECMAScript® 2O21
+export { name16, name17 } from "source4";
+export { import1 as name18, import2 as name19, name20 } from "source5";

tests/test_web/test_utils.py

@@ -1,38 +1,40 @@
+from pathlib import Path
+
 import pytest
 
 from idom.web.utils import resolve_module_exports_from_source
-from tests.general_utils import assert_same_items
+
+
+JS_FIXTURES_DIR = Path(__file__).parent / "js_fixtures"
 
 
 @pytest.mark.parametrize(
-    "module_source, expected_names, expected_references",
+    "text",
     [
-        (
-            "asdfasdfasdf;export{one as One, two as Two};asdfasdf;",
-            ["One", "Two"],
-            [],
-        ),
-        (
-            "asd;export{one as One};asdfasdf;export{two as Two};",
-            ["One", "Two"],
-            [],
-        ),
-        ("asdasd;export default something;", ["default"], []),
-        (
-            "asdasd;export One something;asdfa;export Two somethingElse;",
-            ["One", "Two"],
-            [],
-        ),
-        (
-            "asdasd;export One something;asdfa;export{two as Two};asdfasdf;",
-            ["One", "Two"],
-            [],
-        ),
+        "export default expression;",
+        "export default function (…) { … } // also class, function*",
+        "export default function name1(…) { … } // also class, function*",
+        "export { something as default };",
+        "export { default } from 'some-source';",
+        "export { something as default } from 'some-source';",
     ],
 )
-def test_resolve_module_exports_from_source(
-    module_source, expected_names, expected_references
-):
-    names, references = resolve_module_exports_from_source(module_source)
-    assert_same_items(names, expected_names)
-    assert_same_items(references, expected_references)
+def test_resolve_module_default_exports_from_source(text):
+    names, references = resolve_module_exports_from_source(text)
+    assert names == {"default"} and not references
+
+
+def test_resolve_module_exports_from_source():
+    fixture_file = JS_FIXTURES_DIR / "exports_syntax.js"
+    names, references = resolve_module_exports_from_source(fixture_file.read_text())
+    assert (
+        names
+        == (
+            {f"name{i}" for i in range(1, 21)}
+            | {
+                "functionName",
+                "ClassName",
+            }
+        )
+        and references == {"source1", "source2"}
+    )