SVGTransformList: insertItemBefore() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

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

js
SVGTransformList.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

Inserting a Transformation into the List

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

Specification
Scalable Vector Graphics (SVG) 2
# __svg__SVGNameList__insertItemBefore

Browser compatibility

BCD tables only load in the browser

See also