Support inserting at an index in array

Author: sandy081

src/vs/base/common/jsonEdit.ts

@@ -84,40 +84,36 @@ export function setProperty(text: string, originalPath: JSONPath, value: any, fo
 			return withFormatting(text, edit, formattingOptions);
 		}
 	} else if (parent.type === 'array' && typeof lastSegment === 'number' && Array.isArray(parent.children)) {
-		const insertIndex = lastSegment;
-		if (insertIndex === -1) {
+		if (value !== undefined) {
 			// Insert
 			const newProperty = `${JSON.stringify(value)}`;
 			let edit: Edit;
-			if (parent.children.length === 0) {
-				edit = { offset: parent.offset + 1, length: 0, content: newProperty };
+			if (parent.children.length === 0 || lastSegment === 0) {
+				edit = { offset: parent.offset + 1, length: 0, content: parent.children.length === 0 ? newProperty : newProperty + ',' };
 			} else {
-				const previous = parent.children[parent.children.length - 1];
+				const index = lastSegment === -1 || lastSegment > parent.children.length ? parent.children.length : lastSegment;
+				const previous = parent.children[index - 1];
 				edit = { offset: previous.offset + previous.length, length: 0, content: ',' + newProperty };
 			}
 			return withFormatting(text, edit, formattingOptions);
 		} else {
-			if (value === undefined && parent.children.length >= 0) {
-				//Removal
-				const removalIndex = lastSegment;
-				const toRemove = parent.children[removalIndex];
-				let edit: Edit;
-				if (parent.children.length === 1) {
-					// only item
-					edit = { offset: parent.offset + 1, length: parent.length - 2, content: '' };
-				} else if (parent.children.length - 1 === removalIndex) {
-					// last item
-					const previous = parent.children[removalIndex - 1];
-					const offset = previous.offset + previous.length;
-					const parentEndOffset = parent.offset + parent.length;
-					edit = { offset, length: parentEndOffset - 2 - offset, content: '' };
-				} else {
-					edit = { offset: toRemove.offset, length: parent.children[removalIndex + 1].offset - toRemove.offset, content: '' };
-				}
-				return withFormatting(text, edit, formattingOptions);
+			//Removal
+			const removalIndex = lastSegment;
+			const toRemove = parent.children[removalIndex];
+			let edit: Edit;
+			if (parent.children.length === 1) {
+				// only item
+				edit = { offset: parent.offset + 1, length: parent.length - 2, content: '' };
+			} else if (parent.children.length - 1 === removalIndex) {
+				// last item
+				const previous = parent.children[removalIndex - 1];
+				const offset = previous.offset + previous.length;
+				const parentEndOffset = parent.offset + parent.length;
+				edit = { offset, length: parentEndOffset - 2 - offset, content: '' };
 			} else {
-				throw new Error('Array modification not supported yet');
+				edit = { offset: toRemove.offset, length: parent.children[removalIndex + 1].offset - toRemove.offset, content: '' };
 			}
+			return withFormatting(text, edit, formattingOptions);
 		}
 	} else {
 		throw new Error(`Can not add ${typeof lastSegment !== 'number' ? 'index' : 'property'} to parent of type ${parent.type}`);

src/vs/base/test/common/jsonEdit.test.ts

@@ -118,13 +118,43 @@ suite('JSON - edits', () => {
 		assertEdit(content, edits, '{\n  "x": "y"\n}');
 	});
 
-	test('insert item to empty array', () => {
+	test('insert item at 0', () => {
+		let content = '[\n  2,\n  3\n]';
+		let edits = setProperty(content, [0], 1, formatterOptions);
+		assertEdit(content, edits, '[\n  1,\n  2,\n  3\n]');
+	});
+
+	test('insert item at 0 in empty array', () => {
+		let content = '[\n]';
+		let edits = setProperty(content, [0], 1, formatterOptions);
+		assertEdit(content, edits, '[\n  1\n]');
+	});
+
+	test('insert item at an index', () => {
+		let content = '[\n  1,\n  3\n]';
+		let edits = setProperty(content, [1], 2, formatterOptions);
+		assertEdit(content, edits, '[\n  1,\n  2,\n  3\n]');
+	});
+
+	test('insert item at an index im empty array', () => {
+		let content = '[\n]';
+		let edits = setProperty(content, [1], 1, formatterOptions);
+		assertEdit(content, edits, '[\n  1\n]');
+	});
+
+	test('insert item at end index', () => {
+		let content = '[\n  1,\n  2\n]';
+		let edits = setProperty(content, [2], 3, formatterOptions);
+		assertEdit(content, edits, '[\n  1,\n  2,\n  3\n]');
+	});
+
+	test('insert item at end to empty array', () => {
 		let content = '[\n]';
 		let edits = setProperty(content, [-1], 'bar', formatterOptions);
 		assertEdit(content, edits, '[\n  "bar"\n]');
 	});
 
-	test('insert item', () => {
+	test('insert item at end', () => {
 		let content = '[\n  1,\n  2\n]';
 		let edits = setProperty(content, [-1], 'bar', formatterOptions);
 		assertEdit(content, edits, '[\n  1,\n  2,\n  "bar"\n]');
@@ -160,4 +190,4 @@ suite('JSON - edits', () => {
 		assertEdit(content, edits, '// This is a comment\n[\n  1,\n  "foo"\n]');
 	});
 
-});
+});