JavaScript Tip: Throw an Error if a Required Parameter Is Missing
Michael Hoffmann
Dec 26, 2022
| 1 min read
| 428 views
Michael Hoffmann
Dec 26, 2022
1 min read
| 428 views
Javascript
Default function parameters allow named parameters to be initialized with default values if no value or undefined is passed.
We can use this approach to write a function that throws an error if a required parameter is missing:
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const isRequired = () => {
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throw new Error('Parameter is required!')
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}
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const foo = (bar = isRequired()) => {
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console.log(bar)
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}
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foo() // throws the isRequired error
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foo(undefined) // throws the isRequired error
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foo(false) // logs "false"
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foo(null) // logs "null"
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foo('Test') // logs "true"
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