Add additional informations to tick

i have format for tick:

tick: {
fit: true,
multiline: false,
outer: false,
format: function (x) {
var value = this.api.categories()[x];
if(value.length > 5)
return value.substring(0,5)+"...";
else
return value;
}
},

value - unique attribute. But now - i should cut it by 5 symbol.

and i have click on tick:

_.each(this.chart.element.querySelectorAll('svg g.c3-axis-x .tick text tspan'), (el) => {
el.onclick = (e) => this.someFunction(e)
})

in someFunction() - i want to get unique attribute to get data for current tick.

Earliest i got this attribute like angular.element(e.target).text() but it can contain сropped attribute. How i can get current index? or something else to get full text