parallax/jsPDF · error · Error

Invalid arguments passed to jsPDF.context2d.strokeText

Error message

Invalid arguments passed to jsPDF.context2d.strokeText

What it means

strokeText uses the same guard as fillText: isNaN(x) || isNaN(y) || typeof text !== 'string'. It validates before the stroke-transparency check. maxWidth is optional and NaN-safe (coerced to undefined).

Source

Thrown at src/modules/context2d.js:1366

      maxWidth: maxWidth
    });
  };

  /**
   * Draws text on the canvas (no fill)
   *
   * @name strokeText
   * @function
   * @param text {String} Specifies the text that will be written on the canvas
   * @param x {Number} The x coordinate where to start painting the text (relative to the canvas)
   * @param y {Number} The y coordinate where to start painting the text (relative to the canvas)
   * @param maxWidth {Number} Optional. The maximum allowed width of the text, in pixels
   * @description The strokeText() method draws text (with no fill) on the canvas. The default color of the text is black.
   */
  Context2D.prototype.strokeText = function(text, x, y, maxWidth) {
    if (isNaN(x) || isNaN(y) || typeof text !== "string") {
      console.error("jsPDF.context2d.strokeText: Invalid arguments", arguments);
      throw new Error("Invalid arguments passed to jsPDF.context2d.strokeText");
    }
    if (isStrokeTransparent.call(this)) {
      return;
    }

    maxWidth = isNaN(maxWidth) ? undefined : maxWidth;

    var degs = rad2deg(this.ctx.transform.rotation);
    var scale = this.ctx.transform.scaleX;

    putText.call(this, {
      text: text,
      x: x,
      y: y,
      scale: scale,
      renderingMode: "stroke",
      angle: degs,
      align: this.textAlign,

View on GitHub (pinned to a3930ce03a)

Solutions

  1. Coerce text to String and validate x/y as finite numbers before calling.
  2. Guard the call site and skip when validation fails.
  3. Confirm argument order (text, x, y, [maxWidth]).

Example fix

// before
ctx.strokeText(label.value, pos.x, pos.y);

// after
if (typeof label.value === 'string' && Number.isFinite(+pos.x) && Number.isFinite(+pos.y)) {
  ctx.strokeText(label.value, +pos.x, +pos.y);
}
Defensive patterns

Strategy: validation

Validate before calling

function safeStrokeText(ctx, text, x, y, maxWidth) {
  if (typeof text !== 'string') text = String(text);
  if (!Number.isFinite(+x) || !Number.isFinite(+y)) return;
  ctx.strokeText(text, +x, +y, Number.isFinite(+maxWidth) ? +maxWidth : undefined);
}

Type guard

function isStrokeTextArgs(text, x, y) {
  return typeof text === 'string' && Number.isFinite(+x) && Number.isFinite(+y);
}

Try / catch

try { ctx.strokeText(text, x, y); }
catch (e) { if (!/context2d.strokeText/.test(e.message)) throw e; }

Prevention

When it happens

Trigger: ctx.strokeText(text, x, y) with text not a string, or x/y undefined/NaN/non-numeric; swapping argument order so a number lands in the text slot.

Common situations: Outlining numeric labels without String() coercion; layouts where x/y come from a NaN transform; passing template strings without parsing.

Related errors

AI-assisted analysis of parallax/jsPDF@a3930ce03a (2026-08-13). Data as JSON: /api/errors/501c8e171a95e574. Report an issue: GitHub.