I have this code in Javascript (minesweeper) but I want to add this article in the code . How ?

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Code:
class Minefield {
    /* Construct a minefield with the given width, height, and the number of mines. */
    constructor(width, height, mines) {
        /* Sanitize input parameters. */
        width = Number(width);
        height = Number(height);
        mines = Number(mines);
...