How to override js method?

Question

I want to add some custom functionality to DrawLineString method at mapbox/mapbox-gl-draw https://github.com/mapbox/mapbox-gl-draw/blob/main/src/modes/draw_line_string.js

I can access this function with Draw.constructor.modes.draw_line_string.toDisplayFeatures

  var Draw = new MapboxDraw({
        controls: {
            // point, line_string: true, polygon, trash, combine_features and uncombine_features
            line_string: true,
            trash: true
        },
        displayControlsDefault: false
    });

    console.log('f',Draw.constructor.modes.draw_line_string.toDisplayFeatures);

Is there any simple way to update this function with my code without modifying source files? Thanks

UPD: When I try to use this method, I got createVertex is undefined, and even if I copy this function to main.js the functionality of the drawing tool is broken

 MapboxDraw.modes.draw_line_string.toDisplayFeatures = function (state, geojson, display) {
        const isActiveLine = geojson.properties.id === state.line.id;
        geojson.properties.active = (isActiveLine) ? true : false;
        if (!isActiveLine) return display(geojson);
        // Only render the line if it has at least one real coordinate
        if (geojson.geometry.coordinates.length < 2) return;
        geojson.properties.meta = 'feature';
        display(createVertex(
            state.line.id,
            geojson.geometry.coordinates[state.direction === 'forward' ? geojson.geometry.coordinates.length - 2 : 1],
            `${state.direction === 'forward' ? geojson.geometry.coordinates.length - 2 : 1}`,
            false
        ));
        display(geojson);
        //console.log('geojson', geojson);
    };