GenerateUniqueString Class — drizzle-orm Architecture

Source Code

drizzle-seed/src/services/Generators.ts lines 1470–1511

export class GenerateUniqueString extends AbstractGenerator<{ isUnique?: boolean }> {
	static override readonly entityKind: string = 'GenerateUniqueString';

	private state: { rng: prand.RandomGenerator } | undefined;
	public override isUnique = true;

	override init({ seed }: { seed: number }) {
		const rng = prand.xoroshiro128plus(seed);
		this.state = { rng };
	}

	generate({ i }: { i: number }) {
		if (this.state === undefined) {
			throw new Error('state is not defined.');
		}

		const minStringLength = 7;
		const maxStringLength = 20;
		const stringChars = '1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
		let idx: number,
			strLength: number;
		let currStr: string;

		currStr = '';
		const uniqueStr = i.toString(16);
		[strLength, this.state.rng] = prand.uniformIntDistribution(
			minStringLength,
			maxStringLength - uniqueStr.length,
			this.state.rng,
		);
		for (let j = 0; j < strLength - uniqueStr.length; j++) {
			[idx, this.state.rng] = prand.uniformIntDistribution(
				0,
				stringChars.length - 1,
				this.state.rng,
			);
			currStr += stringChars[idx];
		}

		return currStr.slice(0, 4) + uniqueStr + currStr.slice(4);
	}
}