js canvas计算文字宽度

function getActualWidthOfChats(text,options={}) {
	const {size=13, family = 'Mircrosoft YaHei'} = options
	const canvas = document.createElement('canvas')
	const ctx = canvas.getContext('2d')
	ctx.font = `${size}px ${family}`
	const metrics = ctx.measureText(text)
	const actual = Math.abs(metrics.actualBoundingBoxLeft+Math.abs(metrics.actualBoundingBoxRight))
	return  Math.max(metrics.width, actual)
}