parallax/jsPDF · error · Error

Invalid arguments passed to jsPDF.context2d.rotate

Error message

Invalid arguments passed to jsPDF.context2d.rotate

What it means

rotate validates its single angle argument with isNaN before constructing the rotation matrix. The angle is expected in radians; supplying undefined/NaN/non-numeric throws before any trigonometry runs.

Source

Thrown at src/modules/context2d.js:1461

      throw new Error("Invalid arguments passed to jsPDF.context2d.scale");
    }
    var matrix = new Matrix(scalewidth, 0.0, 0.0, scaleheight, 0.0, 0.0);
    this.ctx.transform = this.ctx.transform.multiply(matrix);
  };

  /**
   * Rotates the current drawing
   *
   * @name rotate
   * @function
   * @param angle {Number} The rotation angle, in radians.
   * @description To calculate from degrees to radians: degrees*Math.PI/180. <br />
   * Example: to rotate 5 degrees, specify the following: 5*Math.PI/180
   */
  Context2D.prototype.rotate = function(angle) {
    if (isNaN(angle)) {
      console.error("jsPDF.context2d.rotate: Invalid arguments", arguments);
      throw new Error("Invalid arguments passed to jsPDF.context2d.rotate");
    }
    var matrix = new Matrix(
      Math.cos(angle),
      Math.sin(angle),
      -Math.sin(angle),
      Math.cos(angle),
      0.0,
      0.0
    );
    this.ctx.transform = this.ctx.transform.multiply(matrix);
  };

  /**
   * Remaps the (0,0) position on the canvas
   *
   * @name translate
   * @function
   * @param x {Number} The value to add to horizontal (x) coordinates

View on GitHub (pinned to a3930ce03a)

Solutions

Pass a finite numeric angle in radians: ctx.rotate(deg * Math.PI / 180).
Guard with Number.isFinite(angle) before calling.
Default to 0 when the angle is unset.

Example fix

// before
ctx.rotate(transform.rotation); // undefined when unset -> throws [110]

// after
const a = Number.isFinite(+transform.rotation) ? +transform.rotation : 0;
ctx.rotate(a);

Defensive patterns

Strategy: validation

Validate before calling

function safeRotate(ctx, angle) {
  const a = Number.isFinite(+angle) ? +angle : 0;
  ctx.rotate(a);
}

Type guard

function isRotateArg(angle) { return Number.isFinite(+angle); }

Try / catch

try { ctx.rotate(angle); }
catch (e) { if (!/context2d.rotate/.test(e.message)) throw e; }

Prevention

Pass angles in radians; convert degrees with deg * Math.PI / 180.
Default unset rotation to 0.
Validate the transform state before applying.

When it happens

Trigger: ctx.rotate(angle) with angle undefined, omitted, or non-numeric; passing degrees without converting to radians produces wrong output but does NOT throw — only NaN/missing args throw.

Common situations: Forgetting to pass the angle; reading rotation from an unset transform state; passing a stringified angle.

Related errors

AI-assisted analysis of parallax/jsPDF@a3930ce03a (2026-08-13). Data as JSON: /api/errors/f63743b6b41bf73e. Report an issue: GitHub.