improve getNodePathFromSourceRange and therefore the ast explorer aswell (#683)

improve getNodePathFromSourceRange and therefore the ast explorer as well

src/lang/getNodePathFromSourceRange.test.ts

@@ -1,6 +1,7 @@
 import { getNodePathFromSourceRange, getNodeFromPath } from './queryAst'
 import { parser_wasm } from './abstractSyntaxTree'
 import { initPromise } from './rust'
+import { Identifier } from './abstractSyntaxTreeTypes'
 
 beforeAll(() => initPromise)
 
@@ -27,4 +28,81 @@ const sk3 = startSketchAt([0, 0])
     expect([node.start, node.end]).toEqual(sourceRange)
     expect(node.type).toBe('CallExpression')
   })
+  it('gets path right for function definition params', () => {
+    const code = `fn cube = (pos, scale) => {
+  const sg = startSketchAt(pos)
+    |> line([0, scale], %)
+    |> line([scale, 0], %)
+    |> line([0, -scale], %)
+
+  return sg
+}
+
+const b1 = cube([0,0], 10)`
+    const subStr = 'pos, scale'
+    const subStrIndex = code.indexOf(subStr)
+    const sourceRange: [number, number] = [
+      subStrIndex,
+      subStrIndex + 'pos'.length,
+    ]
+
+    const ast = parser_wasm(code)
+    const nodePath = getNodePathFromSourceRange(ast, sourceRange)
+    const node = getNodeFromPath<Identifier>(ast, nodePath).node
+
+    expect(nodePath).toEqual([
+      ['body', ''],
+      [0, 'index'],
+      ['declarations', 'VariableDeclaration'],
+      [0, 'index'],
+      ['init', ''],
+      ['params', 'FunctionExpression'],
+      [0, 'index'],
+    ])
+    expect(node.type).toBe('Identifier')
+    expect(node.name).toBe('pos')
+  })
+  it('gets path right for deep within function definition body', () => {
+    const code = `fn cube = (pos, scale) => {
+  const sg = startSketchAt(pos)
+    |> line([0, scale], %)
+    |> line([scale, 0], %)
+    |> line([0, -scale], %)
+
+  return sg
+}
+
+const b1 = cube([0,0], 10)`
+    const subStr = 'scale, 0'
+    const subStrIndex = code.indexOf(subStr)
+    const sourceRange: [number, number] = [
+      subStrIndex,
+      subStrIndex + 'scale'.length,
+    ]
+
+    const ast = parser_wasm(code)
+    const nodePath = getNodePathFromSourceRange(ast, sourceRange)
+    const node = getNodeFromPath<Identifier>(ast, nodePath).node
+    expect(nodePath).toEqual([
+      ['body', ''],
+      [0, 'index'],
+      ['declarations', 'VariableDeclaration'],
+      [0, 'index'],
+      ['init', ''],
+      ['body', 'FunctionExpression'],
+      ['body', 'FunctionExpression'],
+      [0, 'index'],
+      ['declarations', 'VariableDeclaration'],
+      [0, 'index'],
+      ['init', ''],
+      ['body', 'PipeExpression'],
+      [2, 'index'],
+      ['arguments', 'CallExpression'],
+      [0, 'index'],
+      ['elements', 'ArrayExpression'],
+      [0, 'index'],
+    ])
+    expect(node.type).toBe('Identifier')
+    expect(node.name).toBe('scale')
+  })
 })