38 lines
1.3 KiB
TypeScript
38 lines
1.3 KiB
TypeScript
/**
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* RelativeTimeDisplay
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*
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* Deterministic relative time formatting.
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*/
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export class RelativeTimeDisplay {
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/**
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* Formats a date relative to "now".
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* "now" must be passed as an argument for determinism.
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*/
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static format(date: string | Date, now: Date): string {
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const d = typeof date === 'string' ? new Date(date) : date;
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const diffMs = d.getTime() - now.getTime();
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const diffHours = Math.floor(Math.abs(diffMs) / (1000 * 60 * 60));
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const diffDays = Math.floor(Math.abs(diffMs) / (1000 * 60 * 60 * 24));
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if (diffMs < 0) {
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if (diffHours < 1) return 'Just now';
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if (diffHours < 24) return `${diffHours}h ago`;
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if (diffDays === 1) return 'Yesterday';
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if (diffDays < 7) return `${diffDays}d ago`;
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return this.formatAbsolute(d);
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} else {
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if (diffHours < 1) return 'Starting soon';
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if (diffHours < 24) return `In ${diffHours}h`;
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if (diffDays === 1) return 'Tomorrow';
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if (diffDays < 7) return `In ${diffDays} days`;
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return this.formatAbsolute(d);
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}
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}
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private static formatAbsolute(date: Date): string {
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const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
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return `${months[date.getUTCMonth()]} ${date.getUTCDate()}`;
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}
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}
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