perfect/index.js

PERFect, simple JavaScript PERFormance tests

'use strict';

Object.defineProperty(exports, "__esModule", {
    value: true
});
exports.performanceTest = performanceTest;
// detect the global (see https://stackoverflow.com/questions/3277182)
// We do it this way because it works in strict mode AND in browsers that block
// eval with CSP.
//
// We need to do this because of Jest, it doesn't provide a normal global
// context.
var _global;
try {
    _global = (42, eval)('this');
} catch (e) {
    // best guess
    _global = typeof window === 'object' ? window : global || {};
}

// in case the `performance` global isn't available (f.e. in Jest):
var performance = typeof _global.performance !== 'undefined' && _global.performance.now ? _global.performance : { now: Date.now.bind(Date) };

function performanceTest(ref) {
    var description = ref.description;
    var testCases = ref.testCases;
    var iterations = ref.iterations;
    var logResults = ref.logResults;

    iterations = iterations || 500000;
    var results = [];

    if (logResults) {
        console.log(" --- PERFORMANCE TEST: \"" + description + "\"");
        console.log('   -- RUNNING... ');
    }

    for (var test in testCases) {
        results.push(runTestCase(test, iterations, logResults, testCases[test]));
    }

    var slowest = results[0];
    var fastest = results[0];

    for (var i = 0, list = results; i < list.length; i += 1) {
        var result = list[i];

        if (result.averageTime > slowest.averageTime) {
            slowest = result;
        }
        if (result.averageTime < fastest.averageTime) {
            fastest = result;
        }
    }

    if (logResults) {
        console.log('   -- DONE! Results: ');
        console.log("     -- SLOWEST: \"" + slowest.name + "\"");
        console.log("       - total time: " + slowest.totalTime);
        console.log("       - average time: " + slowest.averageTime);
        console.log("     -- FASTEST: \"" + fastest.name + "\"");
        console.log("       - total time: " + fastest.totalTime);
        console.log("       - average time: " + fastest.averageTime);
    }

    return {
        slowest: slowest,
        fastest: fastest
    };
}

function runTestCase(name, iterations, logResults, ref) {
    var setup = ref.setup;
    var before = ref.before;
    var test = ref.test;
    var after = ref.after;
    var cleanup = ref.cleanup;

    if (!test) {
        throw new Error('Um, you need a test.');
    }

    var context = {};

    var totalTime = 0;
    var averageTime;
    var startTime;
    var endTime;

    if (logResults) {
        console.log("     -- TEST CASE: \"" + name + "\" -- ");
    }

    if (setup) {
        setup.call(context, context);
    }

    for (var i = 0; i < iterations; i += 1) {
        if (before) {
            before.call(context, context);
        }

        var start = function () {
            return startTime = performance.now();
        };
        var end = function () {
            return endTime = performance.now();
        };

        var fallbackStartTime = performance.now();

        test.call(context, start, end, context);

        endTime = endTime || performance.now();
        startTime = startTime || fallbackStartTime;

        totalTime += endTime - startTime;

        if (after) {
            after.call(context, context);
        }
    }

    if (cleanup) {
        cleanup.call(context, context);
    }

    averageTime = totalTime / iterations;

    if (logResults) {
        console.log("       - total time: " + totalTime);
        console.log("       - average time: " + averageTime);
    }

    return { name: name, totalTime: totalTime, averageTime: averageTime };
}

var version = exports.version = '1.1.0';