Initial commit

README.md

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+js-range experiments
+
+run benchmark.js or index in tests
+
+comparing for loops against iterators

bench.js

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+import {
+    rangeGenerator,
+    rangeObjectProperty,
+    rangeClosure
+} from './range.js';
+
+const thousand = 1000;
+const million = 1000000;
+
+function benchmark(func) {
+    const iters = 100 * thousand;
+    // pre-heat jit
+    for (let i = 0; i < iters; i++) {
+        func();
+    }
+
+    let start = performance.now();
+    for (let i = 0; i < iters; i++) {
+        func();
+    }
+    let delta = (performance.now() - start) / iters;
+    console.log(`${delta * thousand} us per loop`);
+}
+
+function testFor() {
+    benchmark(() => {
+        let acc = 0;
+        for (let i = 0; i < thousand; i++) {
+            acc += i;
+        }
+        return acc;
+    });
+}
+
+function testOne(func) {
+    benchmark(() => {
+        let acc = 0;
+        for (let i of func(thousand)) {
+            acc += i;
+        }
+        return acc;
+    });
+}
+
+
+console.log('raw for loop');
+testFor();
+console.log('\n');
+
+console.log('rangeGenerator');
+testOne(rangeGenerator);
+console.log('\n');
+
+console.log('rangeObjectProperty');
+testOne(rangeObjectProperty);
+console.log('\n');
+
+console.log('rangeClosure');
+testOne(rangeClosure);
+console.log('\n');

index.html

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+<script type="module" src="bench.js" async></script>
+
+<p>look in console for the benchmark results</p>

package.json

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+{
+    "name": "js-rnage",
+    "type": "module"
+}

range.js

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+export function *rangeGenerator(max) {
+    for (let i = 0; i < max; i++) {
+        yield i;
+    }
+}
+
+function rangeObjectPropertyNext() {
+    if (this.value < this.max) {
+        return {
+            value: this.value++
+        }
+    }
+    return {
+        done: true
+    }
+}
+
+function rangeObjectPropertyIterator() {
+    return {
+        value: 0,
+        max: this.max,
+        next: rangeObjectPropertyNext
+    };
+}
+
+export function rangeObjectProperty(max) {
+    return {
+        max,
+        [Symbol.iterator]: rangeObjectPropertyIterator
+    };
+}
+
+export function rangeClosure(max) {
+    let value = 0;
+    return {
+        [Symbol.iterator]() {
+            return {
+                next() {
+                    if (value < max) {
+                        return {
+                            value: value++
+                        };
+                    }
+                    return {
+                        done: true
+                    };
+                }
+            };
+        }
+    };
+}

results.txt

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+macbook air m1 chrome
+
+raw for loop
+- node: 0.64 us
+- chrome: 0.64 us
+- firefox: 0.63 us
+- safari: 3.89 us
+
+rangeGenerator
+- node: 17.08 us
+- chrome: 17.08 us
+- firefox: 35.06 us
+- safari: 28.89 us
+
+rangeObjectProperty
+- node: 6.55 us
+- chrome: 5.55 us
+- firefox: 5.91 us
+- safari: 23.91 us
+
+rangeClosure
+- node: 6.76 us
+- chrome: 5.76 us
+- firefox: 6.41 us
+- safari: 24.79 us

test.js

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+import {
+    rangeGenerator,
+    rangeObjectProperty,
+    rangeClosure
+} from './range.js';
+
+function testOne(func) {
+    for (let i of func(10)) {
+        console.log(i);
+    }
+}
+
+console.log('rangeGenerator');
+testOne(rangeGenerator);
+console.log('\n');
+
+console.log('rangeObjectProperty');
+testOne(rangeObjectProperty);
+console.log('\n');
+
+console.log('rangeClosure');
+testOne(rangeClosure);
+console.log('\n');