add json validator

main
anna 1 year ago
parent db7cbd27dd
commit e730e85b45
Signed by: fef
GPG Key ID: EC22E476DC2D3D84

@ -0,0 +1,53 @@
export type ObjectType = { [key: string]: Schema };
export type PrimitiveType = "null" | "boolean" | "number" | "string";
export type Schema = PrimitiveType | ObjectType | Array<Schema>;
export function validate<T>(json: any, schema: Schema): T {
if (typeof schema === "string") {
return validatePrimitive(json, schema) as T;
}
if (Array.isArray(schema)) {
if (schema.length !== 1) {
throw new SyntaxError("Invalid schema: Array types must only contain one element");
}
const type = schema[0];
if (!Array.isArray(json)) {
throw new TypeError(`Expected array, got ${typeof json} instead`);
}
const a = [];
for (let e of json) {
a.push(validate(e, type));
}
return a as T;
}
const o: any = {};
for (let prop in schema) {
if (schema.hasOwnProperty(prop)) {
if (!json.hasOwnProperty(prop)) {
throw new TypeError(`Property ${schema[prop]} is missing`);
}
o[prop] = validate(json[prop], schema[prop]) as any;
}
}
return o;
}
function validatePrimitive<T extends PrimitiveType>(json: any, type: T):
PrimitiveToJSType<T> {
if (typeof json === type) {
return json;
} else {
throw new TypeError(`Expected type ${type}, got ${typeof json} instead`);
}
}
type PrimitiveToJSType<T extends PrimitiveType> =
T extends "null" ? null :
T extends "boolean" ? boolean :
T extends "number" ? number :
T extends "string" ? string :
never;
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