/* @flow */

/**
 * This computes the maximum number in an array.
 *
 * This runs on `O(n)`, linear time in respect to the array
 *
 * @param {Array<number>} x sample of one or more data points
 * @returns {number} maximum value
 * @throws {Error} if the the length of x is less than one
 * @example
 * max([1, 2, 3, 4]);
 * // => 4
 */
function max(x /*: Array<number> */) /*:number*/ {
    if (x.length === 0) {
        throw new Error("max requires at least one data point");
    }

    let value = x[0];
    for (let i = 1; i < x.length; i++) {
        // On the first iteration of this loop, max is
        // undefined and is thus made the maximum element in the array
        if (x[i] > value) {
            value = x[i];
        }
    }
    return value;
}

export default max;