2021-05-05 10:13:49 -07:00
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---
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id: 587d7dab367417b2b2512b6e
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title: 使用 every 方法檢查數組中的每個元素是否符合條件
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challengeType: 1
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forumTopicId: 301312
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dashedName: use-the-every-method-to-check-that-every-element-in-an-array-meets-a-criteria
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---
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# --description--
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`every` 方法用於檢測數組中*所有*元素是否都符合指定條件。 如果所有元素滿足條件,返回布爾值 `true`,反之返回 `false`。
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舉個例子,下面的代碼檢測數組 `numbers` 的所有元素是否都小於 10:
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```js
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2021-10-27 15:10:57 +00:00
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const numbers = [1, 5, 8, 0, 10, 11];
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2021-05-05 10:13:49 -07:00
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numbers.every(function(currentValue) {
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return currentValue < 10;
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});
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```
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`every` 方法在這裏會返回 `false`。
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# --instructions--
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在 `checkPositive` 函數中使用 `every` 方法檢查 `arr` 中是否所有元素都是正數。 函數應返回一個布爾值。
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# --hints--
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應使用`every`方法。
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```js
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assert(code.match(/\.every/g));
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```
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`checkPositive([1, 2, 3, -4, 5])` 應返回 `false`。
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```js
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assert.isFalse(checkPositive([1, 2, 3, -4, 5]));
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```
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`checkPositive([1, 2, 3, 4, 5])` 應返回 `true`。
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```js
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assert.isTrue(checkPositive([1, 2, 3, 4, 5]));
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```
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`checkPositive([1, -2, 3, -4, 5])` 應返回 `false`。
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```js
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assert.isFalse(checkPositive([1, -2, 3, -4, 5]));
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```
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# --seed--
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## --seed-contents--
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```js
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function checkPositive(arr) {
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// Only change code below this line
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// Only change code above this line
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}
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2021-10-27 15:10:57 +00:00
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2021-05-05 10:13:49 -07:00
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checkPositive([1, 2, 3, -4, 5]);
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```
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# --solutions--
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```js
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function checkPositive(arr) {
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return arr.every(num => num > 0);
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}
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```
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