walk.cjs•1.26 kB
'use strict';
const noop = function() {};
function ensureFunction(value) {
return typeof value === 'function' ? value : noop;
}
function walk(node, options, context) {
function walk(node) {
enter.call(context, node);
switch (node.type) {
case 'Group':
node.terms.forEach(walk);
break;
case 'Multiplier':
walk(node.term);
break;
case 'Type':
case 'Property':
case 'Keyword':
case 'AtKeyword':
case 'Function':
case 'String':
case 'Token':
case 'Comma':
break;
default:
throw new Error('Unknown type: ' + node.type);
}
leave.call(context, node);
}
let enter = noop;
let leave = noop;
if (typeof options === 'function') {
enter = options;
} else if (options) {
enter = ensureFunction(options.enter);
leave = ensureFunction(options.leave);
}
if (enter === noop && leave === noop) {
throw new Error('Neither `enter` nor `leave` walker handler is set or both aren\'t a function');
}
walk(node);
}
exports.walk = walk;