29 lines
823 B
Markdown
29 lines
823 B
Markdown
# Patroon: Float sort_order (drag-and-drop volgorde)
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## Berekening bij tussenvoeging
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```ts
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function getSortOrder(before: number | null, after: number | null): number {
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if (before === null && after === null) return 1.0
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if (before === null) return after! / 2
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if (after === null) return before + 1.0
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return (before + after) / 2
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}
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```
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## Herindexeer als precisie opraakt
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Trigger wanneer het kleinste verschil tussen twee opeenvolgende items < 0.001 is.
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```ts
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async function reindexIfNeeded(items: { id: string; sort_order: number }[]) {
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const minGap = Math.min(...items.slice(1).map((item, i) =>
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item.sort_order - items[i].sort_order
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))
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if (minGap < 0.001) {
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await Promise.all(items.map((item, i) =>
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prisma.pbi.update({ where: { id: item.id }, data: { sort_order: i + 1.0 } })
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))
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}
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}
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```
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