Node.js code for making a POST API call to NetSuite using OAuth 1.0.

const axios = require('axios');
const CryptoJS = require('crypto-js');



const ACCOUNT_ID = '';
const ENDPOINT = ``;
const AUTH = {
    consumerKey: '',
    consumerSecret: '',
    token: '',
    tokenSecret: ''
};


function generateOAuthHeader(httpMethod, url) {
    try {
        const nonce = Math.random().toString(36).substring(2);
        const timestamp = Math.floor(Date.now() / 1000).toString();
        const signatureMethod = 'HMAC-SHA256';
        const version = '1.0';


        const oauthParams = {
            oauth_consumer_key: AUTH.consumerKey,
            oauth_token: AUTH.token,
            oauth_signature_method: signatureMethod,
            oauth_timestamp: timestamp,
            oauth_nonce: nonce,
            oauth_version: version
        };


        const urlParts = url.split('?');
        const baseUrl = urlParts[0];
        const queryParams = urlParts[1]
            ? Object.fromEntries(urlParts[1].split('&').map(param => {
                const [key, value] = param.split('=');
                return [decodeURIComponent(key), decodeURIComponent(value)];
            }))
            : {};


        const allParams = { ...oauthParams, ...queryParams };
        const sortedParamString = Object.keys(allParams)
            .sort()
            .map(key => `${encodeURIComponent(key)}=${encodeURIComponent(allParams[key])}`)
            .join('&');


        const baseString = [
            httpMethod.toUpperCase(),
            encodeURIComponent(baseUrl),
            encodeURIComponent(sortedParamString)
        ].join('&');


        const signingKey = `${encodeURIComponent(AUTH.consumerSecret)}&${encodeURIComponent(AUTH.tokenSecret)}`;
        const rawSignature = CryptoJS.HmacSHA256(baseString, signingKey);
        const signature = CryptoJS.enc.Base64.stringify(rawSignature);


        oauthParams.oauth_signature = signature;


        const authHeader = 'OAuth realm="' + ACCOUNT_ID + '", ' + Object.keys(oauthParams)
            .map(key => `${encodeURIComponent(key)}="${encodeURIComponent(oauthParams[key])}"`)
            .join(', ');


        console.log("authHeader", authHeader);
        return authHeader;
    } catch (e) {
        log.error('Error @ generateOAuthHeader', e.message);
        throw e;
    }
}


async function sendViaRestAPI(payload) {
    try {
        const url = ENDPOINT
        const response = await axios.post(url, payload, {
            headers: {
                'Authorization': generateOAuthHeader("POST", url),
                'Content-Type': 'application/json',
                'Accept': 'application/vnd.oracle.resource+json; type=singular'
            }
        });


        return response.data;
    } catch (error) {
        console.error('Error @ sendViaRestAPI', error.message);
        throw error;
    }
}


(async () => {
    const payload = {} //Payload


    try {
        const result = await sendViaRestAPI(payload);
        console.log("API Response:" , result?.data.length);
    } catch (err) {
        console.error("API Call Failed:", err);
    }
})();