File size: 4,595 Bytes
1e92f2d
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
import type {
  FlightRouterState,
  Segment,
} from '../../../server/app-render/types'
import { INTERCEPTION_ROUTE_MARKERS } from '../../../shared/lib/router/utils/interception-routes'
import type { Params } from '../../../server/request/params'
import {
  isGroupSegment,
  DEFAULT_SEGMENT_KEY,
  PAGE_SEGMENT_KEY,
} from '../../../shared/lib/segment'
import { matchSegment } from '../match-segments'

const removeLeadingSlash = (segment: string): string => {
  return segment[0] === '/' ? segment.slice(1) : segment
}

const segmentToPathname = (segment: Segment): string => {
  if (typeof segment === 'string') {
    // 'children' is not a valid path -- it's technically a parallel route that corresponds with the current segment's page
    // if we don't skip it, then the computed pathname might be something like `/children` which doesn't make sense.
    if (segment === 'children') return ''

    return segment
  }

  return segment[1]
}

function normalizeSegments(segments: string[]): string {
  return (
    segments.reduce((acc, segment) => {
      segment = removeLeadingSlash(segment)
      if (segment === '' || isGroupSegment(segment)) {
        return acc
      }

      return `${acc}/${segment}`
    }, '') || '/'
  )
}

export function extractPathFromFlightRouterState(
  flightRouterState: FlightRouterState
): string | undefined {
  const segment = Array.isArray(flightRouterState[0])
    ? flightRouterState[0][1]
    : flightRouterState[0]

  if (
    segment === DEFAULT_SEGMENT_KEY ||
    INTERCEPTION_ROUTE_MARKERS.some((m) => segment.startsWith(m))
  )
    return undefined

  if (segment.startsWith(PAGE_SEGMENT_KEY)) return ''

  const segments = [segmentToPathname(segment)]
  const parallelRoutes = flightRouterState[1] ?? {}

  const childrenPath = parallelRoutes.children
    ? extractPathFromFlightRouterState(parallelRoutes.children)
    : undefined

  if (childrenPath !== undefined) {
    segments.push(childrenPath)
  } else {
    for (const [key, value] of Object.entries(parallelRoutes)) {
      if (key === 'children') continue

      const childPath = extractPathFromFlightRouterState(value)

      if (childPath !== undefined) {
        segments.push(childPath)
      }
    }
  }

  return normalizeSegments(segments)
}

function computeChangedPathImpl(
  treeA: FlightRouterState,
  treeB: FlightRouterState
): string | null {
  const [segmentA, parallelRoutesA] = treeA
  const [segmentB, parallelRoutesB] = treeB

  const normalizedSegmentA = segmentToPathname(segmentA)
  const normalizedSegmentB = segmentToPathname(segmentB)

  if (
    INTERCEPTION_ROUTE_MARKERS.some(
      (m) =>
        normalizedSegmentA.startsWith(m) || normalizedSegmentB.startsWith(m)
    )
  ) {
    return ''
  }

  if (!matchSegment(segmentA, segmentB)) {
    // once we find where the tree changed, we compute the rest of the path by traversing the tree
    return extractPathFromFlightRouterState(treeB) ?? ''
  }

  for (const parallelRouterKey in parallelRoutesA) {
    if (parallelRoutesB[parallelRouterKey]) {
      const changedPath = computeChangedPathImpl(
        parallelRoutesA[parallelRouterKey],
        parallelRoutesB[parallelRouterKey]
      )
      if (changedPath !== null) {
        return `${segmentToPathname(segmentB)}/${changedPath}`
      }
    }
  }

  return null
}

export function computeChangedPath(
  treeA: FlightRouterState,
  treeB: FlightRouterState
): string | null {
  const changedPath = computeChangedPathImpl(treeA, treeB)

  if (changedPath == null || changedPath === '/') {
    return changedPath
  }

  // lightweight normalization to remove route groups
  return normalizeSegments(changedPath.split('/'))
}

/**
 * Recursively extracts dynamic parameters from FlightRouterState.
 */
export function getSelectedParams(
  currentTree: FlightRouterState,
  params: Params = {}
): Params {
  const parallelRoutes = currentTree[1]

  for (const parallelRoute of Object.values(parallelRoutes)) {
    const segment = parallelRoute[0]
    const isDynamicParameter = Array.isArray(segment)
    const segmentValue = isDynamicParameter ? segment[1] : segment
    if (!segmentValue || segmentValue.startsWith(PAGE_SEGMENT_KEY)) continue

    // Ensure catchAll and optional catchall are turned into an array
    const isCatchAll =
      isDynamicParameter && (segment[2] === 'c' || segment[2] === 'oc')

    if (isCatchAll) {
      params[segment[0]] = segment[1].split('/')
    } else if (isDynamicParameter) {
      params[segment[0]] = segment[1]
    }

    params = getSelectedParams(parallelRoute, params)
  }

  return params
}