At the time of writing the jsPDF JavaScript library didn't have an underline option for text. This is the code I wrote.

For my project the underline distance of 0.3 always worked. I set it as an optional parameter with 0.3 as default value.

The two functions: underline & underlineCenter:

/** * Write the text and add underline * @param {number} x - Horizontal position. Against left edge of the page. * @param {number} y - Vertical position. Against upper edge of the page. * @param {string} text * @param {object} doc - The jspdf document reference * @param {number} dist - Underline distance under the text */ function underline (text, x, y, doc, dist = 0.3) { /* const textHeight = doc.getTextDimensions(text).h; */ const textWidth = doc.getTextWidth(text); doc.text(text, x, y); doc.setLineWidth(0.2); doc.setDrawColor(0); doc.line(x, y + dist, x + textWidth, y + dist); } // ----------------------------------------------------------------------------- /** * Write the text and add underline. Center the text around the coordinates * @param {number} x - Horizontal position. Against left edge of the page. * @param {number} y - Vertical position. Against upper edge of the page. * @param {string} text * @param {object} doc - The jspdf document reference * @param {number} dist - Underline distance under the text */ function underlineCenter (text, x, y, doc, dist = 0.3) { /* const textHeight = doc.getTextDimensions(text).h; */ const textWidth = doc.getTextWidth(text); doc.text(text, x, y, 'center'); doc.setLineWidth(0.2); doc.setDrawColor(0); doc.line(x - textWidth / 2, y + dist, x + textWidth / 2, y + dist); }