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core

README.md

NPM version npm module downloads per month InteractiveAdvertisingBureau

@iabtcf/core

Ensures consistent encoding and decoding of IAB's Transparency and Consent Framework (TCF) TC Strings and the stateful persistence of the Transparency and Consent information while providing tools for the handling and manipulation of the TCF Global Vendor List data all free and open sourced (License).

Installation

npm

npm install @iabtcf/core --save

yarn

yarn add @iabtcf/core

Using

This example demonstrates the basic use case of a CMP creating a "default all-no" TC string.

import {TCModel, TCString, GVL} from '@iabtcf/core';

/**
 *  the IAB requires CMPs to host their own vendor-list.json files.  This must
 *  be set before creating any instance of the GVL class.
 */
GVL.baseUrl = "http://mydomain.com/cmp/vendorlist";

// create a new TC string
const tcModel = new TCModel(new GVL());

// Some fields will not be populated until a GVL is loaded
tcModel.gvl.readyPromise.then(() => {

  // Set values on tcModel...

  const encodedString = TCString.encode(tcModel);

  console.log(encodedString); // TC string encoded begins with 'C'

});

// take an encoded TC string and decode into a TCModel
const decodedTCModel = TCString.decode(encodedString);

TCModel

Creating a new TCModel

To encode a TCModel a GVL must be included.

import {TCModel} from '@iabtcf/core';

// creates a TCModel
const tcModel = new TCModel();

// to encode you must have a cmpId and cmpVersion
tcModel.cmpId = //{myCMPID}
tcModel.cmpVersion = //{myCMPVersion}

/**
 * we now have a TCString assigned with a GVL which will set vendorListVersion,
 * tcfPolicyVersion and consentLanguage
 */

CMP Meta Fields

This exmple shows how to set the basic fields that all TC strings need to have set.

import {TCModel} from '@iabtcf/core';

const tcModel = new TCModel();
tcModel.cmpId = // my CMP ID
tcModel.cmpVersion = // my CMP Version
tcModel.consentScreen = // On which 'screen' consent was captured; this is a cmp proprietary number encoded into the TC string

Vectors

The TCModel leverages a Set style Vector data structure to set consents, optins, allowed, disclosed, and legitimate interest establishment. Properties that leverage this data structure are:

  • Vendors
    • vendorConsents
    • vendorLegitimateInterests
    • vendorsAllowed
    • vendorsDisclosed
  • Global Purposes
    • purposeConsents
    • purposeLegitimateInterests
  • Special Feature Opt-Ins
    • specialFeatureOptins
  • Publisher
    • publisherConsents
    • publisherCustomConsents
    • publisherLegitimateInterests
    • publisherCustomLegitimateInterests
    • publisherRestrictions
      • This Vector is a special PurposeRestrictionVector of PurposeRestrictions

Example with vendorConsents

The vendorConsents property on the TCModel is a Vector. This example illustrates the methods of a Vector. With the exception of the publisherRestrictions, which implements a different type of PurposeRestrictionVector, all of the above Vectors will have this interface and functionality.

// Give Vendor ID 24 consent
tcModel.vendorConsents.set(24);

console.log(tcModel.vendorConsents.has(24)); // true
console.log(tcModel.vendorConsents.maxId); // 24
console.log(tcModel.vendorConsents.size); // 1

// remove vendor 24
tcModel.vendorConsents.unset(24);
console.log(tcModel.vendorConsents.has(24)); // false
console.log(tcModel.vendorConsents.maxId); // 0
console.log(tcModel.vendorConsents.size); // 0

// give a group of vendors consent
tcModel.vendorConsents.set([24, 14, 24, 100, 102]);
console.log(tcModel.vendorConsents.has(24)); // true
console.log(tcModel.vendorConsents.has(14)); // true
console.log(tcModel.vendorConsents.has(200)); // false
console.log(tcModel.vendorConsents.maxId); // 102
console.log(tcModel.vendorConsents.size); // 5

// loop through all ids 1 to maxId (102 loops)
tcModel.vendorConsents.forEach((hasConsent, vendorId) => {

  // check each id for consent

});

// empty everything
tcModel.vendorConsents.empty();

console.log(tcModel.vendorConsents.has(24)); // false
console.log(tcModel.vendorConsents.maxId); // 0
console.log(tcModel.vendorConsents.size); // 0

Setting Publisher Restrictions

A Publisher Restriction is a restriction placed on a Vendor by a publisher limiting the purposes for which that Vendor is allowed to process personal data. The TCModel.publisherRestrictions is an instance of the PurposeRestrictionVector, which is a vector containing PurposeRestrictions's.

Example of setting publisher restrictions

import {TCModel, PurposeRestriction, RestrictionType} from '@iabtcf/core';

// first you must create a PurposeRestriction
const purposeRestriction = new PurposeRestriction();

purposeRestriction.purposeId = 2;
purposeRestriction.restrictionType = RestrictionType.NOT_ALLOWED;

// vendorID and restriction
tcModel.publisherRestrictions.add(2000, purposeRestriction);

GVL

The GVL class provides two ways to instantiate. Either by passing in a vendor-list.json object to populate it or autoloading a vendor-list.json from a url.

Autoload latest vendor-list.json

Autoloading a vendor-list.json will accept into the constructor a vendor list version number or if nothing or "LATEST" is passed it will load the latest version of the vendor list. NOTE. You must set the GVL.baseUrl parameter before instantiating a GVL instance. If desired the GVL.latestFilename may be set if vendor-list.json is not used.

Loading default filename

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/cmp/';

// loads 'http://cmp.mysupercoolcmp.com/cmp/vendor-list.json'
const gvl = new GVL();

gvl.readyPromise.then(() => {

  // GVL has loaded and it's ready to use

});

Loading with custom filename

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/cmp/';

GVL.latestFilename = 'latest/vendorlist.js';

// loads 'http://cmp.mysupercoolcmp.com/cmp/latest/vendorlist.json'
const gvl = new GVL();

gvl.readyPromise.then(() => {

  // GVL has loaded and it's ready to use

});

Autoload specific version vendor-list.json

Autoloading a specific version requires that you both set the GVL.baseUrl static variable and pass into the constructor the version number you wish to load. Optionally if your filename has a version other than vendor-list-v[VERSION].json you may set a different filename with version as GVL.versionedFilename = 'vendorlist[VERSION].json'; and the token [version] will be replaced with the version number you pass into the constructor.

Loading default filename for version

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/cmp/';

// loads 'http://cmp.mysupercoolcmp.com/cmp/archives/vendor-list-v23.json'
const gvl = new GVL(23);

gvl.readyPromise.then(() => {

  // GVL has loaded and it's ready to use

});

Changing version name scheme

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/cmp/';

GVL.versionedFilename = 'vendorlist[VERSION].json';

// loads 'http://cmp.mysupercoolcmp.com/cmp/vendorlist23.json'
const gvl = new GVL(23);

gvl.readyPromise.then(() => {

  // GVL has loaded and it's ready to use

});

Pass vendor-list.json object

You may also just pass in the json object (not strigified)

import {GVL} from '@iabtcf/core';

const gvl = new GVL(gvljson);

// no need for ready promise because no asynchronous action has occurred
// gvl is ready to use

Change GVL Language

All vendorlists are published by default as english. There are alternate languages that the iab publishes which are essetnailly a vendor list without the vendors. GVL.baseUrl must be set for langauges changes. To load an alternate you simply call gvl.changeLanguage(/**language*/); langauge is the iso639-1 two-letter langauge code. For the full list of iab provided language translations click here. If desired the GVL.languageFilename may be set if purposes-[LANG].json is not used.

Default filename load

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/';

const gvl = new GVL(gvljson);

// loads the French langauge
gvl.changeLanguage('fr').then(() => {

  // French Language GVL is ready for use

});

Changing filename load

import {GVL} from '@iabtcf/core';

const gvl = new GVL(gvljson);

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/';

GVL.langaugeFilename = 'langauges/purp[LANG].json';

// loads the French langauge from 'http://cmp.mysupercoolcmp.com/purpfr.json'
gvl.changeLanguage('fr').then(() => {

  // French Language GVL is ready for use

});

Cloning a GVL with a Non-Default language

When cloning a GVL with a non-default language, make sure that any prior changeLanguage call is resolved. If changeLanguage has not yet resolved, clone will make an http request for the current language but will have no indication of resolving that request since it is synchronous.

import {GVL} from '@iabtcf/core';

const gvl = new GVL();

// Resolving changeLanguage promise using thenables.
gvl.changeLanguage('fr').then(() => {

  const clone = gvl.clone();

})

// Resolving changeLanguage through async/await
const someAsyncFunction = async () => {

  await gvl.changeLanguage('fr');
  const clone = gvl.clone();

}

Get only vendors with a specific feature or purpose under legal basis

A CMP UI may want to group vendors by what purpose they use under what legal basis and/or features. This can be accomplished quite easily by using one of the 6 grouping methods:

  • getVendorsWithConsentPurpose(purposeId)
  • getVendorsWithFeature(featureId)
  • getVendorsWithFlexiblePurpose(purposId)
  • getVendorsWithLegIntPurpose(purposId)
  • getVendorsWithSpecialFeature(featureId)
  • getVendorsWithSpecialPurpose(purposId)

All 6 grouping methods return an IntMap<Vendor> object

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/cmp/';

// loads 'http://cmp.mysupercoolcmp.com/cmp/vendor-list.json'
const gvl = new GVL();

gvl.readyPromise.then(() => {

  const vendorMap = gvl.getVendorsWithConsentPurpose(1);

  // logs all vendor ids who have specified they require consent for purpose 1
  Object.keys(vendorMap).forEach(console.log);

});

Narrow the list of vendors

If loading a CMP would like to show a subset of the Vendor List a filter may be passed to only work with those vendors on the list.

import {GVL} from '@iabtcf/core';

// only needs to be set once per application as this is a static variable
GVL.baseUrl = 'http://cmp.mysupercoolcmp.com/cmp/';

// loads 'http://cmp.mysupercoolcmp.com/cmp/vendor-list.json'
const gvl = new GVL();

gvl.readyPromise.then(() => {

  // now this gvl instance only has these 3 vendors
  gvl.narrowVendorsTo([1,2,3]);

  // will only show the Vendor objects for 1, 2, and 3
  console.log(gvl.vendors);

  // will only return the vendors within the narrowed vendor list
  const vendorsWithLegInt2 = gvl.getVendorsWithLegIntPurpose(2);


});

TCString

Decode an IAB TC String

import {TCString, TCModel} from '@iabtcf/core';

const myTCModel = TCString.decode(encodedTCString);

returns: TCModel

Encode an IAB TC String

import {TCString, TCModel, GVL} from '@iabtcf/core';

/**
 * With v2.0 of the TCF, CMPs are required to host their own vendor-list.json for
 * their client-side scripts to consume.  This GVL class follows the convention
 * outlined in the GVL URL Version scheme.  (latest at vendor-list.json and
 * version specific at archives/vendor-list-v{vendor-list-version}.json
 */
GVL.baseUrl = "http://mydomain.com/cmp/vendorlist";

// we'll get the latest GVL to encode this TCString to
const gvl = new GVL("LATEST");

// have to wait for it to fetch the json
gvl.readyPromise.then(() => {

  const tcModel = new TCModel(gvl);
  const encodedTCString = TCString.encode(tcModel);

  /**
   * this will output a default all "no" encoded string to the console at the
   * lastest GVL version.
   */
  console.log(encodedTCString);

});

Decoding A Segment At A Time

It is possible to pass a reference to an already created TCModel and add individual segments to the model. An important use case for this is if using a globally-scoped TC string and storing the Publisher TC Segment separately in a first-party cookie.

import {TCString, Segment} from '@iabtcf/core';

// if you had a getCookie function that returned just that segment
const publisherTCSegment = getCookie('euconsent-ptc');

let tcModel;

// if you had an asynchronous function to get the cookie from global
getGlobalTCString().then((encodedTCString) => {

  tcModel = TCString.decode(encodedTCString);
  TCString.decode(publisherTCSegment, tcModel);

  // now you have a combined TCModel

});

Encoding Options

Options may be passed to the encoder to override defaults. In most cases the encoder can figure out what segments to include but if the string is surfaced to vendors or for storing in a cookie the encoding is slightly different. The @iabtcf/cmpapi handles this difference and CMPs don't need to worry about it.

import {TCString, Segment} from '@iabtcf/core';

// produces the version of the string for the __tcfapi function
const cmpApiEncodedString = TCString.encode(tcModel, { isForVendors: true });

// Overrides default segments (not recommended unless you know what you're doing)
const encodingOptions = {
  segments: [
    Segment.CORE,
    Segment.VENDORS_DISCLOSED,
    Segment.VENDORS_ALLOWED,
    Segment.PUBLISHER_TC,
  ]
}

const customEncodedString = TCString.encode(tcModel, encodingOptions);

Encoding a Publisher TC Segment

By default if the TCModel.isServiceSpecific = true then encoding a string will include the publisherTC segment. But if TCModel.isServiceSpecific = false then the segment should only be surfaced through the __tcfapi interface and not saved to the global cookie. However, one will need a way to access and save the publisher TC segment separately from the main TC String to store as a first-party cookie. In that case you can use the EncodingOptions to generate only a Publisher TC segment.

const encodingOptions = {
  segments: [Segment.PUBLISHER_TC]
}
const publisherTCSegment = TCString.encode(tcModel, encodingOptions);