Feather Attribution script

feather-attribution.js

// www.featherattribution.com. Brought to you by www.scrapingbee.com and www.freddyfeedback.com

class FeatherAttribution {

	constructor(options) {
		this.storageItems = ['feather_utm_source', 'feather_utm_medium', 'feather_utm_campaign', 'feather_utm_content', 'feather_ref', 'feather_referrer'];
		this.checkExpiryDates();
		this.setOptions(options);
		this.referrer = document.referrer;
		this.ref = this.getParameterByName('ref');
		this.utm_source = this.getParameterByName('utm_source');
		this.utm_medium = this.getParameterByName('utm_medium');
		this.utm_campaign = this.getParameterByName('utm_campaign');
		this.utm_content = this.getParameterByName('utm_content');
		this.setAllLocalStorageItems();
	}

	checkExpiryDates() {
		this.storageItems.forEach(element => {
			const item = localStorage.getItem(element);
			const now = new Date();

			if(item) {
				const itemDetails = JSON.parse(item);
				if (now.getTime() > itemDetails.expiry) {
					localStorage.removeItem(element);
				}
			}
		});
	}

	setOptions(options) {
		if (typeof options !== "undefined") {
			options.hasOwnProperty('expires_in_days') ? this.expires_in_days = options.expires_in_days : 30;
			options.hasOwnProperty('attribution_type_utm') ? this.attribution_type_utm = options.attribution_type_utm : 'first';
			options.hasOwnProperty('attribution_type_ref') ? this.attribution_type_ref = options.attribution_type_ref : 'first';
			options.hasOwnProperty('attribution_type_referrer') ? this.attribution_type_referrer = options.attribution_type_referrer : 'last';
		} else {
			this.expires_in_days = 30;
			this.attribution_type_utm = 'first';
			this.attribution_type_ref = 'first';
			this.attribution_type_referrer = 'last';
		}

		const now = new Date();
		this.expires_on = now.getTime() + (86400000 * this.expires_in_days);
	}

	getParameterByName(name) {
		name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
		var regex = new RegExp("[\\?&]" + name + "=([^&#]*)");
		var results = regex.exec(location.search);
		return results === null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
	}

	truncateString(string) {
		if (string.length < 255) {
			return string;
		}

		return string.substring(0, 255);
	}

	setLocalStorage(key, value, attribution_type) {
		if(!value) {
			return;
		}

		const item = {
			value: this.truncateString(value),
			expiry: this.expires_on,
		}

		if(attribution_type == 'last') {
			localStorage.removeItem(key);
			localStorage.setItem(key, JSON.stringify(item));
		}

		if(attribution_type == 'first' && this.getLocalStorage(key) == null) {
			localStorage.setItem(key, JSON.stringify(item));
		}
	}

	getLocalStorage(key) {
		const itemStr = localStorage.getItem(key);
		
		if (!itemStr) {
			return null;
		}

		const item = JSON.parse(itemStr);

		return item.value;
	}

	setAllLocalStorageItems() {
		this.setLocalStorage('feather_utm_source', this.utm_source, this.attribution_type_utm);
		this.setLocalStorage('feather_utm_medium', this.utm_medium, this.attribution_type_utm);
		this.setLocalStorage('feather_utm_campaign', this.utm_campaign, this.attribution_type_utm);
		this.setLocalStorage('feather_utm_content', this.utm_content, this.attribution_type_utm);
		this.setLocalStorage('feather_ref', this.ref, this.attribution_type_ref);
		this.setLocalStorage('feather_referrer', this.referrer, this.attribution_type_referrer);
	}

	fillFieldsWithValues() {
		this.fillSingleFieldWithValue('utm_source', 'feather_utm_source');
		this.fillSingleFieldWithValue('utm_medium', 'feather_utm_medium');
		this.fillSingleFieldWithValue('utm_campaign', 'feather_utm_campaign');
		this.fillSingleFieldWithValue('utm_content', 'feather_utm_content');
		this.fillSingleFieldWithValue('ref', 'feather_ref');
		this.fillSingleFieldWithValue('referrer', 'feather_referrer');
	}

	fillSingleFieldWithValue(field, value) {
		if(document.getElementById(field)) {
			document.getElementById(field).value = this.getLocalStorage(value);
		} else {
			console.warn('Can not find the field with id = ' + field);
		}
	}

}

window.featherAttribution = new FeatherAttribution({
	expires_in_days: 30,
	attribution_type_utm: 'first',
	attribution_type_ref: 'first',
	attribution_type_referrer: 'last'
});

This script will not be under active development as it was a (very small) side project. Feel free to copy paste the snippet and change it as you like!

If fields are auto-added I’d do it by a class selector on the form. This way you can specify for each form whether you want to the forms auto-added. A second option would be to give the script an extra option parameter to set whether auto-adding is on or off.