extending firebase.database.Reference - firebase

Question

in the old FB I added a helper function to get/set values as follows:
// val() -> get(), resolve with value at ref
// val(value) -> set(value), resolve with value
// val(vals) -> update(vals), resolve with vals
Firebase.prototype.val = function(vals) {
let self=this;
if (!vals) {
return this.once('value').then(
snapshot => {
if (typeof snapshot.val() === 'undefined' || snapshot.val() === null) throw 'INVALID_VALUE';
return snapshot.val();
},
err => {
throw err;
});
}
let singleVal=(vals.constructor != Object); // is singleVal then vals is a single value
if (singleVal ) return this.set(vals); // set single value
if (!singleVal) return this.update(vals).then(() => vals); // update multiple values
};
}
I could then do for example return ref.child(...).val();
This function does not run in V3.
How can I extend firebase in that way in V3 ?
thx!

Answer 1

Here's the solution - I find this extension very handy
// val() -> get(), resolve with value at ref, fails with error.code
// val(value) -> set(value), resolve with value, fails with error.code
// val(vals) -> update(vals), resolve with vals, fails with error.code
firebase.database.Reference.prototype.val = function(vals) {
let path=this.toString().substring(firebase.database().ref().toString().length-1);
let valsAsString = (typeof vals==='string' ? vals : JSON.stringify(vals));
if (!vals) {
return this.once('value').then(
snapshot => {
if (typeof snapshot.val() === 'undefined' || snapshot.val() === null) {
console.log('val('+path+') failed (null) ! '+error.message+' ('+error.code+')');
throw 'INVALID_VALUE';
}
return snapshot.val(); },
error => {
console.log('val('+path+') failed ! '+error.message+' ('+error.code+')');
throw error.code;
});
}
let singleVal=(vals.constructor != Object); // is singleVal then vals is a single value
if (singleVal ) return this.set(vals).then( // set single value
() => {
return vals;
}, error => {
console.log('val('+path+','+valsAsString+') failed ! '+error.message+' ('+error.code+')');
throw error.code;
}
);
return this.update(vals).then( // update multiple values
() => {
return vals;
}, error => {
console.log('val('+path+','+valsAsString+') failed ! '+error.message+' ('+error.code+')');
throw error.code;
}
);
};
}