Spaces:
Runtime error
Runtime error
File size: 1,241 Bytes
b5ea024 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 |
const noop = function() {};
function ensureFunction(value) {
return typeof value === 'function' ? value : noop;
}
export 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, context);
};
|