@edgefirst-dev/data
v0.0.2
Published
TypeScript utilities for safely parsing and handling structured data using DTOs and parsers for FormData, URLSearchParams, and JSON objects.
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Readme
@edgefirst-dev/data
A TypeScript utility library for safely parsing and handling structured data from various sources such as FormData
, URLSearchParams
, JSON objects, and more. The Data
class provides a structured way to define Data Transfer Objects (DTOs), while specialized parsers allow for type-safe access to form fields, URL search parameters, and generic objects.
Installation
bun add @edgefirst-dev/data
Usage
Importing
To use the Data
class, import it from the package root:
import { Data } from "@edgefirst-dev/data";
To use the Parser
base class or one of the specialized parsers (FormParser
, SearchParamsParser
, ObjectParser
), import them from the parser
module:
import {
Parser,
FormParser,
SearchParamsParser,
ObjectParser,
} from "@edgefirst-dev/data/parser";
Data Class
The Data
class is designed to define a set of properties that can be parsed from a source like FormData
, URLSearchParams
, or a JSON object. You subclass Data
to define specific DTOs, using a parser to extract and validate values.
Example
import { Data } from "@edgefirst-dev/data";
import { FormParser } from "@edgefirst-dev/data/parser";
class LoginData extends Data<FormParser> {
get username() {
return this.parser.string("username");
}
get password() {
return this.parser.string("password");
}
}
const formData = new FormData();
formData.append("username", "johndoe");
formData.append("password", "secret");
const loginData = new LoginData(new FormParser(formData));
console.log(loginData.username); // "johndoe"
console.log(loginData.password); // "secret"
Parser Classes
Parser Base Class
The Parser
class is an abstract base class designed for parsing and validating data from structured sources. Specialized parsers extend this class to handle specific data types, ensuring type-safe access to required fields.
FormParser
FormParser
is a specialized parser that wraps FormData
and provides methods to access form fields in a safe and type-validated way.
Example
import { FormParser } from "@edgefirst-dev/data/parser";
const formData = new FormData();
formData.append("username", "johndoe");
const parser = new FormParser(formData);
console.log(parser.string("username")); // "johndoe"
SearchParamsParser
SearchParamsParser
extracts and validates URL query parameters from a URLSearchParams
object, URL
, Request
, or URL string.
Example
import { SearchParamsParser } from "@edgefirst-dev/data/parser";
const url = new URL("https://example.com/?search=query");
const parser = new SearchParamsParser(url);
console.log(parser.get("search")); // "query"
ObjectParser
ObjectParser
safely accesses and validates values within a plain JavaScript object, ensuring type correctness for the retrieved values.
Example
import { ObjectParser } from "@edgefirst-dev/data/parser";
const data = { name: "Alice", age: 30 };
const parser = new ObjectParser(data);
console.log(parser.string("name")); // "Alice"
console.log(parser.number("age")); // 30
Error Handling
All parser classes throw specialized errors when validation fails:
Parser.MissingKeyError
: Thrown when a required key is missing.Parser.InvalidTypeError
: Thrown when a value is not of the expected type.Parser.InvalidInstanceOfError
: Thrown when a value is not an instance of the expected class.Parser.CoercionError
: Thrown when a value cannot be coerced to the expected type.
And each one extends the base Parser.Error
class, so you can catch all parser errors with a single instanceof
condition.
Example
import { ObjectParser } from "@edgefirst-dev/data/parser";
try {
const data = { name: "Alice", age: 30 };
const parser = new ObjectParser(data);
console.log(parser.string("email")); // Throws Parser.MissingKeyError
} catch (error) {
if (error instanceof Parser.MissingKeyError) {
// Handle missing key error
}
if (error instanceof Parser.Error) {
// Handle other parser errors
}
throw error; // Re-throw unexpected errors
}
License
See LICENSE