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			73 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
|   | --- | |||
|  | id: a10d2431ad0c6a099a4b8b52 | |||
|  | title: Everything Be True | |||
|  | isRequired: true | |||
|  | challengeType: 5 | |||
|  | videoUrl: '' | |||
|  | localeTitle: 一切都是真的 | |||
|  | --- | |||
|  | 
 | |||
|  | ## Description
 | |||
|  | <section id="description">检查谓词(第二个参数)是否对集合的所有元素(第一个参数)都是<dfn>真实的</dfn> 。换句话说,您将获得一个对象的数组集合。谓语<code>pre</code>将一个对象的属性,你需要返回<code>true</code> ,如果它的值是<code>truthy</code> 。否则,返回<code>false</code> 。在JavaScript中, <code>truthy</code>值是在布尔上下文中计算时转换为<code>true</code>的值。请记住,您可以通过点表示法或<code>[]</code>表示法访问对象属性。如果卡住,请记得使用<a href="http://forum.freecodecamp.org/t/how-to-get-help-when-you-are-stuck/19514" target="_blank">Read-Search-Ask</a> 。尝试配对程序。编写自己的代码。 </section> | |||
|  | 
 | |||
|  | ## Instructions
 | |||
|  | <section id="instructions"> | |||
|  | </section> | |||
|  | 
 | |||
|  | ## Tests
 | |||
|  | <section id='tests'> | |||
|  | 
 | |||
|  | ```yml | |||
|  | tests: | |||
|  |   - text: '<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code>应该返回true。' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex"), true, "<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code> should return true.");' | |||
|  |   - text: '<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code>应该返回false。' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex"), false, "<code>truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex")</code> should return false.");' | |||
|  |   - text: '<code>truthCheck([{"user": "Tinky-Winky", "sex": "male", "age": 0}, {"user": "Dipsy", "sex": "male", "age": 3}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age")</code>应该返回false。' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"user": "Tinky-Winky", "sex": "male", "age": 2}, {"user": "Dipsy", "sex": "male", "age": 0}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age"), false, "<code>truthCheck([{"user": "Tinky-Winky", "sex": "male", "age": 0}, {"user": "Dipsy", "sex": "male", "age": 3}, {"user": "Laa-Laa", "sex": "female", "age": 5}, {"user": "Po", "sex": "female", "age": 4}], "age")</code> should return false.");' | |||
|  |   - text: '<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat")</code>应该返回false' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat"), false, "<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true}, {"name": "FastFoward", "onBoat": null}], "onBoat")</code> should return false");' | |||
|  |   - text: '<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat")</code>应该返回true' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat"), true, "<code>truthCheck([{"name": "Pete", "onBoat": true}, {"name": "Repeat", "onBoat": true, "alias": "Repete"}, {"name": "FastFoward", "onBoat": true}], "onBoat")</code> should return true");' | |||
|  |   - text: '<code>truthCheck([{"single": "yes"}], "single")</code>应该返回true' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"single": "yes"}], "single"), true, "<code>truthCheck([{"single": "yes"}], "single")</code> should return true");' | |||
|  |   - text: '<code>truthCheck([{"single": ""}, {"single": "double"}], "single")</code>应该返回false' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"single": ""}, {"single": "double"}], "single"), false, "<code>truthCheck([{"single": ""}, {"single": "double"}], "single")</code> should return false");' | |||
|  |   - text: '<code>truthCheck([{"single": "double"}, {"single": undefined}], "single")</code>应返回false' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"single": "double"}, {"single": undefined}], "single"), false, "<code>truthCheck([{"single": "double"}, {"single": undefined}], "single")</code> should return false");' | |||
|  |   - text: '<code>truthCheck([{"single": "double"}, {"single": NaN}], "single")</code>应返回false' | |||
|  |     testString: 'assert.strictEqual(truthCheck([{"single": "double"}, {"single": NaN}], "single"), false, "<code>truthCheck([{"single": "double"}, {"single": NaN}], "single")</code> should return false");' | |||
|  | 
 | |||
|  | ``` | |||
|  | 
 | |||
|  | </section> | |||
|  | 
 | |||
|  | ## Challenge Seed
 | |||
|  | <section id='challengeSeed'> | |||
|  | 
 | |||
|  | <div id='js-seed'> | |||
|  | 
 | |||
|  | ```js | |||
|  | function truthCheck(collection, pre) { | |||
|  |   // Is everyone being true? | |||
|  |   return pre; | |||
|  | } | |||
|  | 
 | |||
|  | truthCheck([{"user": "Tinky-Winky", "sex": "male"}, {"user": "Dipsy", "sex": "male"}, {"user": "Laa-Laa", "sex": "female"}, {"user": "Po", "sex": "female"}], "sex"); | |||
|  | 
 | |||
|  | ``` | |||
|  | 
 | |||
|  | </div> | |||
|  | 
 | |||
|  | 
 | |||
|  | 
 | |||
|  | </section> | |||
|  | 
 | |||
|  | ## Solution
 | |||
|  | <section id='solution'> | |||
|  | 
 | |||
|  | ```js | |||
|  | // solution required | |||
|  | ``` | |||
|  | </section> |