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101 lines
2.1 KiB
Markdown
101 lines
2.1 KiB
Markdown
---
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id: 56533eb9ac21ba0edf2244c9
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title: Accessing Object Properties with Variables
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challengeType: 1
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forumTopicId: 16165
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dashedName: accessing-object-properties-with-variables
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---
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# --description--
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Another use of bracket notation on objects is to access a property which is stored as the value of a variable. This can be very useful for iterating through an object's properties or when accessing a lookup table.
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Here is an example of using a variable to access a property:
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```js
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const dogs = {
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Fido: "Mutt",
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Hunter: "Doberman",
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Snoopie: "Beagle"
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};
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const myDog = "Hunter";
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const myBreed = dogs[myDog];
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console.log(myBreed);
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```
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The string `Doberman` would be displayed in the console.
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Note that we do *not* use quotes around the variable name when using it to access the property because we are using the *value* of the variable, not the *name*.
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# --instructions--
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Set the `playerNumber` variable to `16`. Then, use the variable to look up the player's name and assign it to `player`.
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# --hints--
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`playerNumber` should be a number
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```js
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assert(typeof playerNumber === 'number');
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```
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The variable `player` should be a string
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```js
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assert(typeof player === 'string');
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```
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The value of `player` should be the string `Montana`
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```js
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assert(player === 'Montana');
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```
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You should use bracket notation to access `testObj`
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```js
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assert(/testObj\s*?\[.*?\]/.test(__helpers.removeJSComments(code)));
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```
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You should not assign the value `Montana` to the variable `player` directly.
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```js
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assert(!__helpers.removeJSComments(code).match(/player\s*=\s*"|\'\s*Montana\s*"|\'\s*;/gi));
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```
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You should be using the variable `playerNumber` in your bracket notation
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```js
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assert(/testObj\s*?\[\s*playerNumber\s*\]/.test(__helpers.removeJSComments(code)));
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```
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# --seed--
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## --seed-contents--
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```js
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// Setup
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const testObj = {
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12: "Namath",
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16: "Montana",
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19: "Unitas"
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};
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// Only change code below this line
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const playerNumber = 42; // Change this line
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const player = testObj; // Change this line
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```
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# --solutions--
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```js
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const testObj = {
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12: "Namath",
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16: "Montana",
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19: "Unitas"
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};
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const playerNumber = 16;
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const player = testObj[playerNumber];
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```
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