OpenFDABuilder.ts•1.95 kB
/*
* Copyright (c) 2025 Ythalo Saldanha
* Licensed under the MIT License
*/
// The ContextType type defines the valid OpenFDA API contexts that can be used with the OpenFDABuilder.
// These correspond to different OpenFDA drug endpoints, such as:
// - 'ndc': National Drug Code Directory
// - 'label': Drug Labeling
// - 'event': Adverse Event Reporting
type ContextType = "ndc" | "label" | "event";
/**
* The OpenFDABuilder class helps construct URLs for the OpenFDA API.
*
* Usage:
* - Set the context (such as 'label', 'ndc', or 'event') using the context() method.
* - Set the search query using the search() method.
* - Optionally set the result limit using the limit() method (default is 1).
* - Call build() to assemble and return the final API URL.
*
* Example:
* const url = new OpenFDABuilder()
* .context('label')
* .search('openfda.brand_name:"Advil"')
* .limit(1)
* .build();
*
* The build() method will throw an error if any required parameter is missing.
* The API key is read from the OPENFDA_API_KEY environment variable.
*/
export class OpenFDABuilder {
private url = "https://api.fda.gov/drug/";
private params = new Map<string, string | number>();
context(context: ContextType): this {
this.params.set("context", context);
return this;
}
search(query: string): this {
this.params.set("search", query);
return this;
}
limit(max: number = 1): this {
this.params.set("limit", max);
return this;
}
build(): string {
const context = this.params.get("context");
const search = this.params.get("search");
const limit = this.params.get("limit");
const apiKey = process.env.OPENFDA_API_KEY;
if (!context || !search || !limit) {
throw new Error("Missing required parameters: context, search, or limit");
}
return `${this.url}${context}.json?api_key=${apiKey}&search=${search}&limit=${limit}`;
}
}