If-Else Chain VS Switch(true)
JavaScript performance comparison
Revision 9 of this test case created by KDO
Info
This test is to attempt to determine if there is any notable performance difference when using switch(true) instead of a chain of if-else statements.
Preparation code
<script>
var strs = ['apple', 'banana', 'pear', 'lemon', 'grape', 'orange'],
len = strs.length;
</script>
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Testing in unknown unknown
| Test |
Ops/sec |
If-Else Chain |
for (var i = len; i--;) {
var str = strs[i];
if (/p{2}le/.test(str)) var some_var = 'found apple';
else if (/(an){2}a/.test(str)) var some_var = 'found banana';
else if (/^[a-z][a-z][a-z][a-z]$/.test(str)) var some_var = 'found pear';
else if (str.indexOf("lemon") != -1) var some_var = 'found lemon';
else if (/ape/.test(str)) var some_var = 'found grape';
else var some_var = 'found else (orange)';
}
|
pending… |
switch(true) |
for (var i = len; i--;) {
var str = strs[i];
switch (true) {
case / p {
2
}
le / .test(str):
return 'found apple';
case / (an) {
2
}
a / .test(str):
return 'found banana';
case / ^ [a - z][a - z][a - z][a - z] $ / .test(str):
return 'found pear';
case (str.indexOf("lemon") != -1):
return 'found lemon';
case / ape / .test(str):
return 'found grape';
default:
return 'found else (orange)';
}
}
|
pending… |
ternary |
for (var i = len; i--;) {
var str = strs[i];
var some_var = /p{2}le/.test(str) ? 'found apple' : /(an){2}a/.test(str) ? 'found banana' : /^[a-z][a-z][a-z][a-z]$/.test(str) ? 'found pear' : (str.indexOf("lemon") != -1) ? 'found lemon' : /ape/.test(str) ? 'found grape' : 'found else (orange)';
}
|
pending… |
short-circuit |
for (var i = len; i--;) {
var str = strs[i];
var some_var = /p{2}le/.test(str) && 'found apple' || /(an){2}a/.test(str) && 'found banana' || /^[a-z][a-z][a-z][a-z]$/.test(str) && 'found pear' || (str.indexOf("lemon") != -1) && 'found lemon' || /ape/.test(str) && 'found grape' || 'found else (orange)';
}
|
pending… |
if-else chain 2 |
for (var i = len; i--;) {
var str = strs[i];
var some_var = '';
if (/p{2}le/.test(str)) some_var = 'found apple';
else if (/(an){2}a/.test(str)) some_var = 'found banana';
else if (/^[a-z][a-z][a-z][a-z]$/.test(str)) some_var = 'found pear';
else if (str.indexOf("lemon") != -1) some_var = 'found lemon';
else if (/ape/.test(str)) some_var = 'found grape';
else some_var = 'found else (orange)';
}
|
pending… |
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