Calender customize and translation

Hi
I’m trying to Calender CSS customize, and translation by hard coding @ mage-eventpress\js\calendar.min.js

I would like to set the days of the week in Japanese, but I don’t understand .js that well yet. If anyone has any information, please let me know.

/* calendar button text position adjustment*/
button {
padding: 3px;
padding-top: 5px;
}

/* Calendar year and month*/
.equinox .month-label {
text-align: right;
font-size: 1.7em;
float: right;
padding-top: 0.1em;
}

/* Calendar day-of-week text*/
.equinox .week-header {
font-size: 0.8em;
text-transform: uppercase;
color: #999; }
}

/* Calendar date text*/
.equinox .date-label {
text-align: right;
font-size: 0.9em;
color: #34A853; }
}