31 lines
1.7 KiB
JavaScript
31 lines
1.7 KiB
JavaScript
// Minimal JSON-schema subset validator (node built-ins only).
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// Supports: type, required, enum, const, properties, items, minimum, oneOf, anyOf.
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const typeOk = (t, v) =>
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t === "array" ? Array.isArray(v)
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: t === "null" ? v === null
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: t === "integer" ? Number.isInteger(v)
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: t === "object" ? v !== null && typeof v === "object" && !Array.isArray(v)
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: typeof v === t;
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export function validate(schema, value, path = "$") {
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const errs = [];
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if (schema.type) {
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const types = [].concat(schema.type);
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if (!types.some((t) => typeOk(t, value))) return [`${path}: expected ${types.join("|")}`];
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}
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if (schema.enum && !schema.enum.includes(value)) errs.push(`${path}: not in enum ${JSON.stringify(schema.enum)}`);
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if ("const" in schema && value !== schema.const) errs.push(`${path}: expected ${JSON.stringify(schema.const)}`);
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if (schema.minimum !== undefined && typeof value === "number" && value < schema.minimum) errs.push(`${path}: below minimum ${schema.minimum}`);
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if (typeOk("object", value)) {
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for (const k of schema.required || []) if (!(k in value)) errs.push(`${path}: missing "${k}"`);
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for (const [k, s] of Object.entries(schema.properties || {})) if (k in value) errs.push(...validate(s, value[k], `${path}.${k}`));
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}
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if (Array.isArray(value) && schema.items) value.forEach((v, i) => errs.push(...validate(schema.items, v, `${path}[${i}]`)));
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if (schema.anyOf && !schema.anyOf.some((s) => validate(s, value, path).length === 0)) errs.push(`${path}: matches no anyOf branch`);
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if (schema.oneOf) {
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const n = schema.oneOf.filter((s) => validate(s, value, path).length === 0).length;
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if (n !== 1) errs.push(`${path}: matches ${n} oneOf branches (need 1)`);
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}
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return errs;
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}
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