SVGTransformList: insertItemBefore() method

The insertItemBefore() method of the SVGTransformList interface inserts a new item into the list at the specified position.

The first item is indexed at 0. The inserted item is the item itself and not a copy.

If newItem is already in a list, it is removed from its previous list before it is inserted into this list.
If the item is already in this list, note that the index of the item to insert before is before the removal of the item.
If the index is equal to 0, then the new item is inserted at the front of the list.
If the index is greater than or equal to numberOfItems, then the new item is appended to the end of the list.

Syntax

insertItemBefore(newItem, index)

Parameters

newItem: An SVGTransform item that is inserted into the list.
index: An integer; the index where the new item should be inserted as an unsigned long.

Return value

An SVGTransform object; the inserted item from the list.

Exceptions

NoModificationAllowedError DOMException: Thrown if SVGTransformList corresponds to a read-only attribute or when the object itself is read-only.

Examples

undefined

Inserting a Transformation into the List

html

<svg width="200" height="200" id="mySvg">
  <rect width="100" height="100" fill="blue" />
</svg>

const svgElement = document.querySelector("svg");
const rectElement = svgElement.querySelector("rect");

// Access the transform list of the <rect> element
const transformList = rectElement.transform.baseVal;

// Create a new translate transformation
const translateTransform = svgElement.createSVGTransform();
translateTransform.setTranslate(50, 50);

// Insert the translation transformation at the beginning of the list
transformList.insertItemBefore(translateTransform, 0);

// The transformation list length and type
console.log(`Number of transformations: ${transformList.length}`); // Output: 1
console.log(`Transformation Type: ${transformList.getItem(0).type}`); // Output: 2 (e.g. SVG_TRANSFORM_TRANSLATE)

Specifications

Scalable Vector Graphics (SVG) 2