Basic node interaction: API call Get_node_info()

IOTA101_696A395DC61B.js

// The snippet is a part of the IOTA Developer Essentials project. You can reach it at https://hribek25.github.io/IOTA101/
// Complete description and story behind the snippet is available at: https://hribek25.github.io/IOTA101/Allchapters_javascript.ipynb.html#696A395DC61B
// Requirement: IOTA Javascript Library (!npm install iota.lib.js)

var IOTA = require('../../node_modules/iota.lib.js/lib/iota'); // load iota.lib.js

// # ctor initialization of the iota.lib.js library
var iota = new IOTA({
    'provider': 'https://nodes.thetangle.org:443'
});

// basic API call to double check health conditions
iota.api.getNodeInfo(function (error, success) {
    if (error) {
        // unable to perform getNodeInfo call
        console.error(error);
    } else {
        // result is printed out
        console.log(success);
        
        // Basic check whether node is in sync or not
        // Elementary rule is that "latestMilestoneIndex" should equal to "latestSolidSubtangleMilestoneIndex" or be very close
        if (Math.abs(success['latestMilestoneIndex'] - success['latestSolidSubtangleMilestoneIndex']) > 3) {
            console.log('\r\nNode is probably not synced!');
        } else {
            console.log('\r\nNode is probably synced!');
        }
    }
});