Ensures other in-page digital marketing technologies have access to CMP transparency and consent information for the iab. Transparency and Consent Framework (TCF).
npm install @didomi/iabtcf-cmpapi
Ensures other in-page digital marketing technologies have access to CMP transparency and consent information for the IAB's Transparency and Consent Framework (TCF).
CmpApi is the only class needed to provide in-page digital marketing technologies access to a CMP transparency and consent information.
The process involves setting the state of a few properties and/or a validly ecnoded TC string
npm
``
npm install @iabtcf/cmpapi --save
yarn
`
yarn add @iabtcf/cmpapi
To create an instance of the CmpApi. Pass in your Cmp ID (assigned by IAB) and the Version (integer), and whether or not this instance is configured to use a service-specific scope to the constructor.
A custom commands object map may optionally be passed to extend the page-call functionality as well.
``javascript
import {CmpApi} from '@iabtcf/cmpapi';
const cmpApi = new CmpApi(1, 3, true);
``
During construction of the CmpApi, the window.__tcfapi stub is replacedCmpApi
with 's own function for handling window.__tcfapi command requests.
Commands that were waiting to be executed in the stub are filtered out if not
valid. Ping and custom commands are executed and removed from the queue while
all other commands remain queued until a valid TC
string
is set.
Note: After creation, window.__tcfapi will respond to "ping" commands and custom commands only. All other commandsupdate()
will be queue until is called for the first time.
In the specification, events occur and registered callbacks are called "whenever the TC String is changed and a new one is available". CmpApi will trigger an event whenever update is called.``javascript``
cmpApi.update(encodedTCString || '' || null);
update() may be called either an encoded TC''
string
an empty string () or null.
* Encoded TC string, CmpApi will decode the string and respond to TCData with the decoded values.gdprApplies
* will be set to true
* Empty string (), CmpApi will respond to TCData with the correct structure but all primitive values will be empty.gdprApplies
* will be set to true
* , CmpApi will respond to TCData with the correct structure but all primitive values will be empty.gdprApplies
* will be set to false
CmpApi needs to know when you are going to show the user the UI to the usereventStatus
to recapture consent in order to set the correct.boolean
The second parameter is a letting CmpApi know that the UI is nowfalse
visible to the user (it defaults to ).
``javascript
// showing the ui to the user
cmpApi.update(encodedTCString, true);
/* CMP gathers user preferences /
cmpApi.update(updatedEncodedTCString, false);
``
``javascript
// not showing the ui to the user, only one update is needed
cmpApi.update(encodedTCString, false);
``
``javascript
// showing the ui to the user
cmpApi.update('', true);
/* CMP gathers user preferences /
cmpApi.update(updatedEncodedTCString, false);
``
``javascript
// only one update needed to let CmpApi that gdpr doesn't apply
cmpApi.update(null);
``
provides a disable method. Calling the disabled method will put the CmpApi
into a permanent error state. Only ping and custom commands will continue to be executed
for page requests.javascript
cmpApi.disable();
``Custom Commands
has an optional parameter to pass in your map of custom commands.
CmpApi will not perform any validation on custom commands. The CMP is
responsible for handling validations and errors. Custom function signatures
must have a callback and may define additonal params that will be passed from
the calling script.Example
``javascriptimport {CmpApi} from '@iabtcf/cmpapi';
const cmpApi = new CmpApi(1, 3, false, {
'bingo': (callback, dogName) => {
callback(
There was a farmer who had a dog, and ${dogName} was his name-o); },
'connectBones': (callback, startBone, endBone) => {
callback(
The ${startBone} bone is connected to the ${endBone} bone.); },
});
const songLyricCallback = (lyrics, success) => {
if(success) {
console.log(lyrics)
} else {
console.error('Error: could not get song lyrics')
}
}
__tcfapi('bingo', 2, songLyricCallback, 'Bingo');
// ouput: There was a farmer who had a dog, and Bingo was his name-o
__tcfapi('connectBones', 2, songLyricCallback, 'knee', 'thigh');
// ouput: The knee bone is connected to the thigh bone
``
$3
Beginning in 1.1.0, if a custom command is defined that overlaps with a built-in command (, "getTCData", "getInAppTCData", "getVendorList") then the custom command will act as a "middleware" being passed the built-in command's response and expected to pass along the response when finished.Note:
"addEventListener" and "removeEventListener" can __not__ be overwritten. "addEventListener" utilizes the "getTCData" command, so to modify TCData responses, write a Built-In custom command for that command and both "getTCData" and "addEventListener" will utilize it. If the "removeEventListener" command is also used with a custom "getTCData" command, note that "removeEventListener" will not return tcData but rather a boolean that indicates if the listener was removed. So it is important to add a check, otherwise the CmpApi will catch that error and the callbacks will return with tcData: null.Example
``javascriptimport {CmpApi} from '@iabtcf/cmpapi';
const cmpApi = new CmpApi(1, 3, false, {
'getTCData': (next, tcData, status) => {
/*
If using with 'removeEventListener' command, add a check to see if tcData is not a boolean. /
if (typeof tcData !== 'boolean') {
// tcData will be constructed via the TC string and can be added to here
tcData.reallyImportantExtraProperty = true;
}
// pass data and status along
next(tcData, status);
},
});
``
Note: If the function is not called with the TCData` object, then the caller's callback will not be executed.