I always wished for default value support in JavaScript function parameters. Every time I came across a default value requirement, the OR operator did its role.
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function show (message) { message = message || "I am not assigned"; console.log(message);}show(); // "I am not assigned"show('Boom'); // "Boom" |
We do not have to default assign in this way from ES6. Here is the updated code as per ES6.
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function show (message = "I am not assigned") { console.log(message);}show(); // "I am not assigned"show('Boom'); // "Boom" |
But there is a difference in working of 2 code segments. In the traditional method(first method), "I am not assigned"will be printed in following cases.
- No argument is passed
- Any falsy value is passed like empty string,
undefined, 0,false,null
In the new technique, "I am not assigned"will be printed only when we are not passing any values or explicitly passing undefined.
Summary: This new default argument assignment helps to deliver more readable code.
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