If you are new to JavaScript or have only recently encountered it in your development work, you may be feeling frustrated. All languages have their quirks - but developers moving from a server-side language based on strong typing can be confused. I was like that, a few years ago, when I was thrust into becoming a full-time JavaScript developer, and there were a lot of things I wish I'd known at the beginning. In this article, I'm going to share some of my quirks and hopefully I can share with you some of the experiences that have given me a lot of headaches. This isn't a complete list - just a partial list - but hopefully it opens your eyes to the power of this language, and things you may have once considered a hindrance.
When we create a new variable, we usually verify whether the value of the variable is null (null) or undefined. This is a verification that often needs to be considered for JavaScript programming.
If you write it directly, it would look like this:
##if (variable1 !== null || variable1 ! == undefined || variable1 !== '') { let variable2 = variable1; }
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##let variable2 = variable1 || '';
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If you don’t believe it, try it in the console of the Google Chrome developer panel !
//Example of null value let variable1 = null;
let variable2 = variable1 || '';
console.log(variable2);//Example of undefined value let variable1 = undefined;
let variable2 = variable1 || '';
console.log( variable2);//Output: '' //Normal situation let variable1 = 'hi there';
let variable2 = variable1 || '';
console.log(variable2);//Output: 'hi there' |
2. Array
let a = new Array(); a[0] = "myString1"; a[1] = "myString2"; a[2] = "myString3";
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"myString1", "myString2", "myString3"];
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if (x > 10) {
big = true;
}
else {
big = false;
}
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true : false;
Greatly simplifies the amount of code!
3;
1;minusCount = minusCount -
minusCount -- ; y*= 10;
// x=15
var re = "\d+(.)+\d+", |
result = re.exec("padding 01234 text text 56789 padding");console.log(result) ; //"01234 text text 56789"
##After simplification:
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7. If condition optimizationAlthough it is very simple, it is still worth mentioning. Before simplification:
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##if (likeJavaScript ===
true)
Simplified: | if (likeJavaScript)
if ( c!=
true ) {
}
After simplification:
9. Function parameter optimizationI personally tend to use the method of obtaining object elements to access function parameters. Of course, this is a matter of opinion! Usually used version:
means 10000000.Before simplification:
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