Note: this is a work in progress.

A polyfill for the DOM Geometry Interfaces Level 1 for JavaScript runtimes that don’t include them.

domgeom is available as an npm package:

npm install --save domgeom

import { 
	DOMMatrix, 
	DOMMatrixReadOnly, 
	DOMPoint, 
	DOMPointReadOnly, 
	DOMRect,
	DOMRectReadOnly, 
	DOMQuad 
} from 'domgeom';

Object.assign(globalThis, {
	DOMMatrix,
	DOMMatrixReadOnly,
	DOMPoint,
	DOMPointReadOnly,
	DOMRect,
	DOMRectReadOnly,
	DOMQuad
});

• DOMMatrixReadOnly.prototype.toString() throws an Error instead of an "InvalidStateError" DOMException.
• The read-only interfaces are not actually read only (it just seemed tedious to implement).
• Strings get parsed according to the <transform-list> CSS syntax in the DOMMatrix() and DOMMatrixReadOnly(), as well as in DOMMatrix.prototype.setMatrixValue(), instead of throwing. However, the parser is looser than its browser counterpart, and ignores most <length> units (e.g. 10px is interpreted as 10). Percentages are always resolved to value/100.

Also note that due to numerical errors there may be slight differences in the matrix values compared to browser environments. In tests, rounding the values before comparisons is recommended.

• CSS Transforms Level 2: Mathematical Description of Transform Functions
• CSS tokenization code is taken from Selery.