service-titan-api/src/auth/serviceTitanAuth.mjs

A module for authenticating and accessing the ServiceTitan API.

// src/auth/serviceTitanAuth.mjs
import axios from "axios";

export default class ServiceTitanAuth {
  /**
   * @param {Object} options
   * @param {string} options.clientId - Your ServiceTitan Client ID
   * @param {string} options.clientSecret - Your ServiceTitan Client Secret
   * @param {string} [options.environment='integration'] - Environment ('integration' or 'production')
   */
  constructor({ clientId, clientSecret, environment = "integration" }) {
    if (!clientId || !clientSecret) {
      throw new Error("clientId and clientSecret are required");
    }
    this.clientId = clientId;
    this.clientSecret = clientSecret;
    this.environment = environment;
    this.authUrl =
      environment === "integration"
        ? "https://auth-integration.servicetitan.io/connect/token"
        : "https://auth.servicetitan.io/connect/token";
    this.accessToken = null;
    this.expiresAt = 0;
  }

  /**
   * Returns a valid access token. If the current token is expired or about to expire,
   * it will automatically fetch a new one.
   * @returns {Promise<string>} The ServiceTitan access token.
   */
  async getAccessToken() {
    if (this.accessToken && Date.now() < this.expiresAt) {
      return this.accessToken;
    }
    return this.fetchNewToken();
  }

  /**
   * Fetches a new access token from the ServiceTitan OAuth API using axios.
   * @returns {Promise<string>} The new access token.
   */
  async fetchNewToken() {
    const body = new URLSearchParams();
    body.append("grant_type", "client_credentials");
    body.append("client_id", this.clientId);
    body.append("client_secret", this.clientSecret);

    try {
      const response = await axios.post(this.authUrl, body.toString(), {
        headers: { "Content-Type": "application/x-www-form-urlencoded" },
      });
      const data = response.data;
      this.accessToken = data.access_token;
      // Subtract a safety margin (30 seconds) from expires_in.
      this.expiresAt = Date.now() + (data.expires_in - 30) * 1000;
      return this.accessToken;
    } catch (error) {
      const status = error.response ? error.response.status : "Unknown status";
      const statusText = error.response
        ? error.response.statusText
        : "Unknown error";
      const errorData = error.response
        ? JSON.stringify(error.response.data)
        : error.message;
      throw new Error(
        `Error fetching token: ${status} ${statusText}: ${errorData}`
      );
    }
  }
}