79 lines
1.6 KiB
JavaScript
79 lines
1.6 KiB
JavaScript
'use strict'
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module.exports = visitParents
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var convert = require('unist-util-is/convert')
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var CONTINUE = true
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var SKIP = 'skip'
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var EXIT = false
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visitParents.CONTINUE = CONTINUE
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visitParents.SKIP = SKIP
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visitParents.EXIT = EXIT
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function visitParents(tree, test, visitor, reverse) {
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var is
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if (typeof test === 'function' && typeof visitor !== 'function') {
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reverse = visitor
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visitor = test
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test = null
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}
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is = convert(test)
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one(tree, null, [])
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// Visit a single node.
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function one(node, index, parents) {
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var result = []
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var subresult
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if (!test || is(node, index, parents[parents.length - 1] || null)) {
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result = toResult(visitor(node, parents))
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if (result[0] === EXIT) {
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return result
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}
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}
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if (node.children && result[0] !== SKIP) {
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subresult = toResult(all(node.children, parents.concat(node)))
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return subresult[0] === EXIT ? subresult : result
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}
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return result
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}
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// Visit children in `parent`.
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function all(children, parents) {
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var min = -1
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var step = reverse ? -1 : 1
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var index = (reverse ? children.length : min) + step
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var result
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while (index > min && index < children.length) {
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result = one(children[index], index, parents)
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if (result[0] === EXIT) {
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return result
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}
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index = typeof result[1] === 'number' ? result[1] : index + step
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}
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}
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}
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function toResult(value) {
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if (value !== null && typeof value === 'object' && 'length' in value) {
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return value
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}
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if (typeof value === 'number') {
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return [CONTINUE, value]
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}
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return [value]
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}
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