GeneratePostcode Class — drizzle-orm Architecture

Source Code

drizzle-seed/src/services/Generators.ts lines 2411–2466

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

	private state: {
		rng: prand.RandomGenerator;
		templates: string[];
	} | undefined;
	override uniqueVersionOfGen = GenerateUniquePostcode;

	override init({ count, seed }: { count: number; seed: number }) {
		super.init({ count, seed });

		const rng = prand.xoroshiro128plus(seed);
		const templates = ['#####', '#####-####'];

		const maxPostcodeLength = Math.max(...templates.map((template) => template.length));
		if (this.stringLength !== undefined && this.stringLength < maxPostcodeLength) {
			throw new Error(
				`You can't use postcode generator with a db column length restriction of ${this.stringLength}. Set the maximum string length to at least ${maxPostcodeLength}.`,
			);
		}

		this.state = { rng, templates };
	}

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

		let idx: number, postcodeNumber: number;

		[idx, this.state.rng] = prand.uniformIntDistribution(0, this.state.templates.length - 1, this.state.rng);
		const template = this.state.templates[idx]!;

		const iterArray = [...template.matchAll(/#/g)];
		const placeholdersCount = iterArray.length;

		[postcodeNumber, this.state.rng] = prand.uniformIntDistribution(
			0,
			Math.pow(10, placeholdersCount) - 1,
			this.state.rng,
		);
		const postcode = fillTemplate({
			template,
			placeholdersCount,
			values: [...String(postcodeNumber)],
			defaultValue: '0',
		});

		return postcode;
	}
}