parallax/jsPDF · error · Error

Invalid arguments passed to jsPDF.context2d.moveTo

Error message

Invalid arguments passed to jsPDF.context2d.moveTo

What it means

context2d.moveTo() is the Canvas 2D API equivalent for beginning a new sub-path at the given coordinates. jsPDF validates both x and y with isNaN() to prevent NaN values from propagating into the PDF path data, which would produce corrupt output. NaN typically arises from undefined variables, failed type coercion, or math operations on non-numeric values. The function also logs the invalid arguments to console.error before throwing.

Source

Thrown at src/modules/context2d.js:802

    this.path = [
      {
        type: "begin"
      }
    ];
  };

  /**
   * Moves the path to the specified point in the canvas, without creating a line
   *
   * @name moveTo
   * @function
   * @param x {Number} The x-coordinate of where to move the path to
   * @param y {Number} The y-coordinate of where to move the path to
   */
  Context2D.prototype.moveTo = function(x, y) {
    if (isNaN(x) || isNaN(y)) {
      console.error("jsPDF.context2d.moveTo: Invalid arguments", arguments);
      throw new Error("Invalid arguments passed to jsPDF.context2d.moveTo");
    }

    var pt = this.ctx.transform.applyToPoint(new Point(x, y));

    this.path.push({
      type: "mt",
      x: pt.x,
      y: pt.y
    });
    this.ctx.lastPoint = new Point(x, y);
  };

  /**
   * Creates a path from the current point back to the starting point
   *
   * @name closePath
   * @function
   * @description The closePath() method creates a path from the current point back to the starting point.

View on GitHub (pinned to a3930ce03a)

Solutions

Ensure coordinates are finite numbers: ctx.moveTo(Number(x) || 0, Number(y) || 0)
Validate before calling: if (isFinite(x) && isFinite(y)) ctx.moveTo(x, y)
Check for undefined: ctx.moveTo(x ?? 0, y ?? 0)
Debug by checking console.error output which prints the actual arguments passed

Example fix

// before
var x = parseFloat(element.style.left); // NaN if not set
ctx.moveTo(x, 0); // throws

// after
ctx.moveTo(parseFloat(element.style.left) || 0, 0);
// or
var x = Number(element.style.left) || 0;
ctx.moveTo(x, 0);

Defensive patterns

Strategy: validation

Validate before calling

// Validate coordinates before calling moveTo
function safeMoveTo(ctx, x, y) {
  x = Number(x);
  y = Number(y);
  if (!isFinite(x) || !isFinite(y)) {
    throw new TypeError('moveTo requires finite numbers for x and y');
  }
  ctx.moveTo(x, y);
}

Type guard

/**
 * @param {*} value
 * @returns {boolean}
 */
function isFiniteNumber(value) {
  return typeof value === 'number' && isFinite(value);
}

Try / catch

try {
  ctx.moveTo(x, y);
} catch (e) {
  if (e.message.includes('moveTo')) {
    ctx.moveTo(0, 0); // default to origin
  } else throw e;
}

Prevention

Use isFinite() to check coordinates before path operations
Initialize coordinate variables to 0 rather than leaving undefined
Check console.error output which logs the actual arguments before the throw

When it happens

Trigger: Calling ctx.moveTo(undefined, 10) or ctx.moveTo(NaN, 10). Passing a variable computed from division by zero. Using parseFloat('abc') which returns NaN. Passing null for coordinates. Destructuring from an object where the coordinate keys don't exist.

Common situations: Rendering SVG paths where coordinate parsing fails on malformed data. Drawing functions that receive undefined when an element is not found in the DOM. Animation loops where a coordinate becomes NaN at boundary conditions. Porting Canvas code where some values are lazily initialized.

Related errors

AI-assisted analysis of parallax/jsPDF@a3930ce03a (2026-08-13). Data as JSON: /api/errors/732a08faa4b2796e. Report an issue: GitHub.