TextMetrics: alphabeticBaseline property

The read-only alphabeticBaseline property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the alphabetic 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.alphabeticBaseline; // -0;