JSFiddle - React, Tailwind, and code Playground

JavaScript

function lerp(start, end, t) {
    return (1 - t) * start + t * end;
}

function rgbToCSS(rgb) {
    return 'rgb(' + Math.round(rgb[0]) + ',' +
                    Math.round(rgb[1]) + ',' +
                    Math.round(rgb[2]) + ')';
}

function getColor(t) {
    var colors = [
        [153, 173, 255], [204, 218, 255], [245, 245, 255],
        [252, 255, 214], [255, 243, 163], [255, 163, 82],
        [251, 98,  81]
    ];
    var domain = [-0.63, 0.165, 0.33, 0.495, 0.66, 0.825, 2.057];

    if (t <= domain[0]) {
        return colors[0];
    }

    if (t >= domain[domain.length - 1]) {
        return colors[colors.length - 1];
    }

    for (var i = 0; t > domain[i]; i++);

    var from = colors[i - 1];
    var to = colors[i];
    t = (t - domain[i - 1]) / (domain[i] - domain[i - 1]);
    return [
        lerp(from[0], to[0], t),
        lerp(from[1], to[1], t),
        lerp(from[2], to[2], t)
    ];
}

var canvas = document.createElement('canvas');
canvas.width = 800;
canvas.height = 100;
var context = canvas.getContext('2d');
for (var i = 0; i < canvas.width; i++) {
    context.fillStyle = rgbToCSS(getColor(lerp(-0.63, 2.057, i / canvas.width)));
    context.fillRect(i, 0, 1, canvas.height);
}
document.body.appendChild(canvas);