how to make an arc rotating around a center in ExtendScript After Effects?

Question

I want to make a loading animation in After Effects using scripts

I get no arc only white screen with shape layer there

and this is what gets rendered in the app

This is my code that doesn't work

app.project.close(CloseOptions.DO_NOT_SAVE_CHANGES);
app.newProject();
app.beginUndoGroup("Create Comp");

// Create a new composition with a solid layer
var comp = app.project.items.addComp("My Composition", 1920, 1080, 1, 10, 24);

comp.openInViewer();

var solid = comp.layers.addSolid([1, 1, 1], "My Solid", 1920, 1080, 1, 10);

// Create a new shape layer
var shapeLayer = comp.layers.addShape();
// shapeLayer.moveToStart();
shapeLayer.enabled= true;

// Set position of the shape layer
var shapePosition = shapeLayer.property("ADBE Transform Group").property("ADBE Position");
shapePosition.setValue([960,540]);

var path = shapeLayer.property("ADBE Root Vectors Group").addProperty("ADBE Vector Shape - Group");
// make a arc
path.property("ADBE Vector Shape").setValue(new Shape());
path.property("ADBE Vector Shape").value.vertices = [[0, 0], [100, 100], [200, 0]];
path.property("ADBE Vector Shape").value.inTangents = [[-50, -50], [0, 0]];
path.property("ADBE Vector Shape").value.outTangents = [[0, 0], [50, 50]];
path.property("ADBE Vector Shape").value.closed = true;
path.enabled = true;

var stroke = shapeLayer.property("ADBE Root Vectors Group").addProperty("ADBE Vector Graphic - Stroke");
stroke.property("ADBE Vector Stroke Width").setValue(5);
stroke.property("ADBE Vector Stroke Color").setValue([1, 0, 0]);
stroke.enabled = true;

var fill = shapeLayer.property("ADBE Root Vectors Group").addProperty("ADBE Vector Graphic - Fill");
fill.property("ADBE Vector Fill Color").setValue([1, 0, 0]);
fill.enabled = true;

// Create an animation for the rotation property
var rotation = shapeLayer.property("ADBE Transform Group").property("ADBE Rotate Z");
rotation.setValueAtTime(0, 0);
rotation.setValueAtTime(5, 180);

// Set the composition duration to 10 seconds
comp.duration = 10;

app.endUndoGroup();

Answer 1

Properties in AE can't be set by assigning values to them. You need to use the setValue() method. Additionally in this instance you want to set the values of the shape object before assigning it to the path property.

var theShape = new Shape();
theShape.vertices = [[0, 0], [100, 100], [200, 0]];
theShape.inTangents = [[-50, -50], [0, 0]];
theShape.outTangents = [[0, 0], [50, 50]];
theShape.closed = true;
path.property("ADBE Vector Shape").setValue(theShape);

Also, as an AE developer: