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| 1 | +/** |
| 2 | + * RFC 6901 JSON Pointer utilities. |
| 3 | + * No external dependencies — manual implementation. |
| 4 | + */ |
| 5 | + |
| 6 | +/** Escape a segment for use in a pointer. ~ → ~0, / → ~1 */ |
| 7 | +function escapeSegment(segment) { |
| 8 | + if (typeof segment !== 'string') return String(segment); |
| 9 | + return segment.replace(/~/g, '~0').replace(/\//g, '~1'); |
| 10 | +} |
| 11 | + |
| 12 | +/** Unescape a segment. ~1 → /, ~0 → ~ (order matters) */ |
| 13 | +function unescapeSegment(segment) { |
| 14 | + if (typeof segment !== 'string') return segment; |
| 15 | + return segment.replace(/~1/g, '/').replace(/~0/g, '~'); |
| 16 | +} |
| 17 | + |
| 18 | +/** |
| 19 | + * Parse a pointer into segments. /data/items/0 → ['data', 'items', '0'] |
| 20 | + * @param {string} pointer - RFC 6901 pointer (e.g. "/data/items/0") |
| 21 | + * @returns {string[]} Unescaped segments (empty array for root) |
| 22 | + */ |
| 23 | +function parsePointer(pointer) { |
| 24 | + if (!pointer || typeof pointer !== 'string') return []; |
| 25 | + const trimmed = pointer.startsWith('/') ? pointer.slice(1) : pointer; |
| 26 | + if (!trimmed) return []; |
| 27 | + return trimmed.split('/').map(unescapeSegment); |
| 28 | +} |
| 29 | + |
| 30 | +/** |
| 31 | + * Append a segment to a pointer. |
| 32 | + * @param {string} pointer - Base pointer (e.g. "/data") |
| 33 | + * @param {string|number} segment - Segment to append (e.g. "items" or 0) |
| 34 | + * @returns {string} New pointer (e.g. "/data/items") |
| 35 | + */ |
| 36 | +export function append(pointer, segment) { |
| 37 | + const normalized = pointer === '' || pointer === '/' ? '' : pointer.replace(/\/$/, ''); |
| 38 | + const escaped = escapeSegment(String(segment)); |
| 39 | + return normalized ? `${normalized}/${escaped}` : `/${escaped}`; |
| 40 | +} |
| 41 | + |
| 42 | +/** |
| 43 | + * Get value at pointer in object. |
| 44 | + * @param {Object} obj - Root object |
| 45 | + * @param {string} pointer - RFC 6901 pointer (e.g. "/data/items/0/name") |
| 46 | + * @returns {*} Value at path, or undefined |
| 47 | + */ |
| 48 | +export function getValueByPointer(obj, pointer) { |
| 49 | + const segments = parsePointer(pointer); |
| 50 | + let current = obj; |
| 51 | + for (const seg of segments) { |
| 52 | + if (current == null) return undefined; |
| 53 | + current = current[seg]; |
| 54 | + } |
| 55 | + return current; |
| 56 | +} |
| 57 | + |
| 58 | +/** |
| 59 | + * Set value at pointer. Creates missing intermediate objects/arrays. |
| 60 | + * @param {Object} obj - Root object to modify |
| 61 | + * @param {string} pointer - RFC 6901 pointer (e.g. "/data/items/0/name") |
| 62 | + * @param {*} value - Value to set |
| 63 | + */ |
| 64 | +export function setValueByPointer(obj, pointer, value) { |
| 65 | + const segments = parsePointer(pointer); |
| 66 | + if (segments.length === 0) return; |
| 67 | + |
| 68 | + let current = obj; |
| 69 | + for (let i = 0; i < segments.length - 1; i += 1) { |
| 70 | + const seg = segments[i]; |
| 71 | + const nextSeg = segments[i + 1]; |
| 72 | + const isNextArrayIndex = /^\d+$/.test(String(nextSeg)); |
| 73 | + |
| 74 | + if (!(seg in current)) { |
| 75 | + current[seg] = isNextArrayIndex ? [] : {}; |
| 76 | + } |
| 77 | + current = current[seg]; |
| 78 | + } |
| 79 | + |
| 80 | + const lastSeg = segments[segments.length - 1]; |
| 81 | + current[lastSeg] = value; |
| 82 | +} |
| 83 | + |
| 84 | +/** |
| 85 | + * Remove array item at pointer. Pointer must point to an array element. |
| 86 | + * @param {Object} obj - Root object to modify |
| 87 | + * @param {string} pointer - Pointer to array item (e.g. "/data/items/0") |
| 88 | + * @returns {boolean} True if removed, false otherwise |
| 89 | + */ |
| 90 | +export function removeArrayItemByPointer(obj, pointer) { |
| 91 | + const segments = parsePointer(pointer); |
| 92 | + if (segments.length < 2) return false; |
| 93 | + |
| 94 | + const lastSeg = segments[segments.length - 1]; |
| 95 | + const index = parseInt(lastSeg, 10); |
| 96 | + if (!Number.isInteger(index) || index < 0) return false; |
| 97 | + |
| 98 | + const parentSegments = segments.slice(0, -1); |
| 99 | + let current = obj; |
| 100 | + for (let i = 0; i < parentSegments.length - 1; i += 1) { |
| 101 | + const seg = parentSegments[i]; |
| 102 | + if (current == null || !(seg in current)) return false; |
| 103 | + current = current[seg]; |
| 104 | + } |
| 105 | + |
| 106 | + const parentKey = parentSegments[parentSegments.length - 1]; |
| 107 | + const array = current?.[parentKey]; |
| 108 | + if (current == null || !(parentKey in current) || !Array.isArray(array)) return false; |
| 109 | + |
| 110 | + if (index < 0 || index >= array.length) return false; |
| 111 | + |
| 112 | + array.splice(index, 1); |
| 113 | + return true; |
| 114 | +} |
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