preact-render-to-string/src/util.js

// DOM properties that should NOT have "px" added when numeric
export const IS_NON_DIMENSIONAL = /acit|ex(?:s|g|n|p|$)|rph|ows|mnc|ntw|ine[ch]|zoo|^ord/i;

export const objectKeys = Object.keys || (obj => {
	let keys = [];
	for (let i in obj) if (obj.hasOwnProperty(i)) keys.push(i);
	return keys;
});

export let encodeEntities = s => String(s)
	.replace(/&/g, '&')
	.replace(/</g, '&lt;')
	.replace(/>/g, '&gt;')
	.replace(/"/g, '&quot;');

export let indent = (s, char) => String(s).replace(/(\n+)/g, '$1' + (char || '\t'));

export let isLargeString = (s, length, ignoreLines) => (String(s).length>(length || 40) || (!ignoreLines && String(s).indexOf('\n')!==-1) || String(s).indexOf('<')!==-1);

const JS_TO_CSS = {};

// Convert an Object style to a CSSText string
export function styleObjToCss(s) {
	let str = '';
	for (let prop in s) {
		let val = s[prop];
		if (val!=null) {
			if (str) str += ' ';
			// str += jsToCss(prop);
			str += JS_TO_CSS[prop] || (JS_TO_CSS[prop] = prop.replace(/([A-Z])/g,'-$1').toLowerCase());
			str += ': ';
			str += val;
			if (typeof val==='number' && IS_NON_DIMENSIONAL.test(prop)===false) {
				str += 'px';
			}
			str += ';';
		}
	}
	return str || undefined;
}

/**
 * Copy all properties from `props` onto `obj`.
 * @param {object} obj Object onto which properties should be copied.
 * @param {object} props Object from which to copy properties.
 * @returns {object}
 * @private
 */
export function assign(obj, props) {
	for (let i in props) obj[i] = props[i];
	return obj;
}

/**
 * Reconstruct Component-style `props` from a VNode.
 * Ensures default/fallback values from `defaultProps`:
 * Own-properties of `defaultProps` not present in `vnode.attributes` are added.
 * @param {import('preact').VNode} vnode The VNode to get props for
 * @returns {object} The props to use for this VNode
 */
export function getNodeProps(vnode) {
	let props = assign({}, vnode.attributes);
	props.children = vnode.children;

	let defaultProps = vnode.nodeName.defaultProps;
	if (defaultProps!==undefined) {
		for (let i in defaultProps) {
			if (props[i]===undefined) {
				props[i] = defaultProps[i];
			}
		}
	}

	return props;
}