TextMetrics: ideographicBaseline property

The read-only ideographicBaseline property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the ideographic baseline of the line box, in CSS pixels.

const canvas = document.createElement("canvas");
const ctx = canvas.getContext("2d");
const text = ctx.measureText("foo"); // returns TextMetrics object

text.ideographicBaseline; // -1.201171875;