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54 lines
1.4 KiB
54 lines
1.4 KiB
3 years ago
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## Half a million
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### Using variables as keys
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One possible and very useful way to get something from an object is using a
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variable value. Sometimes you don't know in advance what the key will be.
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Using variables allows your code to be flexible, let's see how to do it
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```js
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let greeting = 'hello'
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let say = { hello: 'my friend', hoy: 'mate' }
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// Here when we access it will use
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console.log(say[greeting]) // -> 'my friend'
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// It is exactly the same as doing
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console.log(say['hello']) // -> 'my friend'
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// But if we change the value of our variable:
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greeting = 'hoy'
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// The same code now returns another value
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console.log(say[greeting]) // -> 'mate'
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```
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We are using the `value` of the variable, not the `identifier` to access the
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property, so:
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```js
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console.log(say[greeting]) // -> 'mate'
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console.log(say['greeting']) // -> undefined
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console.log(say.greeting) // -> undefined
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// greeting is the identifier, but we use it's value, here `'hoy'`
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```
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### Instructions
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In this exercise, we will do a heist.
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Our intel already worked the plan out and we are able to provide you with 2
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variables:
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- a `vault` object
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- a `secret` string
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You must use the `secret` value as a key to access the matching value from the
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`vault` and assign it to a variable `loot`.
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You must then replace the value from the vault by a message of your choice.
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> I sure hope you didn't do anything stupid, Jackie. \
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> ― Ray Nicolette
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