web: Add bindings for remaining field APIs

lib/binding_web/binding.c

@@ -331,6 +331,11 @@ void ts_node_named_child_wasm(const TSTree *tree, uint32_t index) {
   marshal_node(TRANSFER_BUFFER, ts_node_named_child(node, index));
 }
 
+void ts_node_child_by_field_id_wasm(const TSTree *tree, uint32_t field_id) {
+  TSNode node = unmarshal_node(tree);
+  marshal_node(TRANSFER_BUFFER, ts_node_child_by_field_id(node, field_id));
+}
+
 void ts_node_next_sibling_wasm(const TSTree *tree) {
   TSNode node = unmarshal_node(tree);
   marshal_node(TRANSFER_BUFFER, ts_node_next_sibling(node));

lib/binding_web/binding.js

@@ -302,6 +302,17 @@ class Node {
     return unmarshalNode(this.tree);
   }
 
+  childForFieldId(fieldId) {
+    marshalNode(this);
+    C._ts_node_child_by_field_id_wasm(this.tree[0], fieldId);
+    return unmarshalNode(this.tree);
+  }
+
+  childForFieldName(fieldName) {
+    const fieldId = this.tree.language.fields.indexOf(fieldName);
+    if (fieldId !== -1) return this.childForFieldId(fieldId);
+  }
+
   get childCount() {
     marshalNode(this);
     return C._ts_node_child_count_wasm(this.tree[0]);
@@ -586,10 +597,13 @@ class TreeCursor {
     return unmarshalNode(this.tree);
   }
 
-  currentFieldName() {
+  currentFieldId() {
     marshalTreeCursor(this);
-    const fieldId = C._ts_tree_cursor_current_field_id_wasm(this.tree[0]);
-    return this.tree.language.fields[fieldId];
+    return C._ts_tree_cursor_current_field_id_wasm(this.tree[0]);
+  }
+
+  currentFieldName() {
+    return this.tree.language.fields[this.currentFieldId()];
   }
 
   gotoFirstChild() {
@@ -641,6 +655,23 @@ class Language {
     return C._ts_language_version(this[0]);
   }
 
+  get fieldCount() {
+    return this.fields.length - 1;
+  }
+
+  fieldIdForName(fieldName) {
+    const result = this.fields.indexOf(fieldName);
+    if (result !== -1) {
+      return result;
+    } else {
+      return null;
+    }
+  }
+
+  fieldNameForId(fieldId) {
+    return this.fields[fieldName] || null;
+  }
+
   static load(url) {
     let bytes;
     if (

lib/binding_web/exports.json

@@ -36,6 +36,7 @@
   "_ts_language_symbol_name",
   "_ts_language_symbol_type",
   "_ts_language_version",
+  "_ts_node_child_by_field_id_wasm",
   "_ts_node_child_count_wasm",
   "_ts_node_child_wasm",
   "_ts_node_children_wasm",

lib/binding_web/test/node-test.js

@@ -116,6 +116,35 @@ describe("Node", () => {
     })
   });
 
+  describe('.childForFieldName()', () => {
+    it('returns null when the node has no children', () => {
+      tree = parser.parse("class A { b() {} }");
+
+      const classNode = tree.rootNode.firstChild;
+      assert.equal(classNode.type, 'class_declaration');
+
+      const classNameNode = classNode.childForFieldName('name');
+      assert.equal(classNameNode.type, 'identifier');
+      assert.equal(classNameNode.text, 'A');
+
+      const bodyNode = classNode.childForFieldName('body');
+      assert.equal(bodyNode.type, 'class_body');
+      assert.equal(bodyNode.text, '{ b() {} }');
+
+      const methodNode = bodyNode.firstNamedChild;
+      assert.equal(methodNode.type, 'method_definition');
+      assert.equal(methodNode.text, 'b() {}');
+
+      const methodNameNode = methodNode.childForFieldName('name');
+      assert.equal(methodNameNode.type, 'property_identifier');
+      assert.equal(methodNameNode.text, 'b');
+
+      const paramsNode = methodNode.childForFieldName('parameters');
+      assert.equal(paramsNode.type, 'formal_parameters');
+      assert.equal(paramsNode.text, '()');
+    });
+  });
+
   describe(".nextSibling and .previousSibling", () => {
     it("returns the node's next and previous sibling", () => {
       tree = parser.parse("x10 + 1000");

lib/binding_web/tree-sitter-web.d.ts

@@ -71,6 +71,8 @@ declare module 'web-tree-sitter' {
       toString(): string;
       child(index: number): SyntaxNode | null;
       namedChild(index: number): SyntaxNode | null;
+      childForFieldId(fieldId: number): SyntaxNode | null;
+      childForFieldName(fieldName: string): SyntaxNode | null;
 
       descendantForIndex(index: number): SyntaxNode;
       descendantForIndex(startIndex: number, endIndex: number): SyntaxNode;
@@ -97,6 +99,7 @@ declare module 'web-tree-sitter' {
       reset(node: SyntaxNode): void;
       delete(): void;
       currentNode(): SyntaxNode;
+      currentFieldId(): number;
       currentFieldName(): string;
       gotoParent(): boolean;
       gotoFirstChild(): boolean;
@@ -115,8 +118,15 @@ declare module 'web-tree-sitter' {
       getEditedRange(other: Tree): Range;
       getLanguage(): any;
     }
-    namespace Language {
-        function load(url: string): Promise<any>
+
+    class Language {
+      static load(): Promise<Language>;
+
+      readonly version: number;
+      readonly fieldCount: number;
+
+      fieldNameForId(fieldId: number): string | null
+      fieldIdForName(fieldName: string): number | null
     }
   }