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
54
55
56
57
|
var assert = require('assert')
module.exports = dashAst
/**
* Call `cb` on each node in `ast`. If `cb` is an object, `cb.enter` is called before processing a Node's children,
* and `cb.leave` is called after processing a Node's children.
*/
function dashAst (ast, cb) {
assert(ast && typeof ast === 'object' && typeof ast.type === 'string',
'dash-ast: ast must be an AST node')
if (typeof cb === 'object') {
assert(typeof cb.enter === 'function' || typeof cb.leave === 'function',
'dash-ast: visitor must be an object with enter/leave functions')
walk(ast, null, cb.enter || undefined, cb.leave || undefined)
} else {
assert(cb && typeof cb === 'function',
'dash-ast: callback must be a function')
walk(ast, null, cb, undefined)
}
}
function walk (node, parent, enter, leave) {
var cont = enter !== undefined ? enter(node, parent) : undefined
if (cont === false) return
for (var k in node) {
if (has(node, k)) {
if (k === 'parent') continue
var v = node[k]
if (isNode(v)) {
walk(v, node, enter, leave)
} else if (Array.isArray(v)) {
walkArray(v, node, enter, leave)
}
}
}
if (leave !== undefined) leave(node, parent)
}
function walkArray (nodes, parent, enter, leave) {
for (var i = 0; i < nodes.length; i++) {
if (isNode(nodes[i])) walk(nodes[i], parent, enter, leave)
}
}
function isNode (node) {
return typeof node === 'object' && node && typeof node.type === 'string'
}
function has (obj, prop) {
return Object.prototype.hasOwnProperty.call(obj, prop)
}
|
