melt/dist/utils/string.js

The next generation of Melt UI. Built for Svelte 5.

export function unique(value, seen = new WeakMap()) {
    // Handle primitives
    if (value === null)
        return "null";
    if (typeof value !== "object") {
        if (typeof value === "bigint")
            return `bigint:${value}`;
        if (typeof value === "symbol")
            return `symbol:${value.toString()}`;
        if (typeof value === "function")
            return `function:${value.toString()}`;
        if (Number.isNaN(value))
            return "NaN";
        return `${typeof value}:${value}`;
    }
    // Handle circular references
    if (seen.has(value))
        return "[Circular]";
    seen.set(value, true);
    try {
        // Handle arrays
        if (Array.isArray(value)) {
            const items = value.map((item) => unique(item, seen));
            return `array:[${items.join(",")}]`;
        }
        // Handle specific object types
        if (value instanceof Date) {
            return `date:${value.toISOString()}`;
        }
        if (value instanceof RegExp) {
            return `regexp:${value.toString()}`;
        }
        if (value instanceof Map) {
            const entries = Array.from(value.entries())
                .sort(([a], [b]) => unique(a).localeCompare(unique(b)))
                .map(([k, v]) => `${unique(k, seen)}:${unique(v, seen)}`);
            return `map:{${entries.join(",")}}`;
        }
        if (value instanceof Set) {
            const items = Array.from(value)
                .map((item) => unique(item, seen))
                .sort();
            return `set:{${items.join(",")}}`;
        }
        // Handle plain objects
        const entries = Object.entries(value)
            .sort(([a], [b]) => a.localeCompare(b))
            .map(([k, v]) => `${k}:${unique(v, seen)}`);
        return `object:{${entries.join(",")}}`;
    }
    finally {
        seen.delete(value);
    }
}