locomotive-boilerplate/assets/scripts/utils/maths.js

/**
 * Clamp value
 * @param {number}  min - start value
 * @param {number}  max - end value
 * @param {number}  a   - alpha value
 * @return {number} clamped value
 */

const clamp = (min = 0, max = 1, a) => Math.min(max, Math.max(min, a))


/**
 * Calculate lerp
 * @param {number}  x   - start value
 * @param {number}  y   - end value
 * @param {number}  a   - alpha value
 * @return {number} lerp value
 */

const lerp = (x, y, a) => x * (1 - a) + y * a


/**
 * Calculate inverted lerp
 * @param {number}  x   - start value
 * @param {number}  y   - end value
 * @param {number}  a   - alpha value
 * @return {number} inverted lerp value
 */

const invlerp = (x, y, a) => clamp((a - x)/(y - x))


/**
 * Round number to the specified precision.
 *
 * This function is necessary because `Number.prototype.toPrecision()`
 * and `Number.prototype.toFixed()`
 *
 * @param  {number}  number      - The floating point number to round.
 * @param  {number}  [precision] - The number of digits to appear after the decimal point.
 * @return {number} The rounded number.
 */
const roundNumber = (number, precision = 2) => {
    return Number.parseFloat(number.toPrecision(precision));
}


export {
    clamp,
    lerp,
    invlerp,
    roundNumber
}