[size=medium]If a number is used where a boolean value is expected, the number is converted to TRue unless the
number is 0 or NaN , which are converted to false . If a string is used where a boolean value is expected,
it is converted to true except for the empty string, which is converted to false . null and the undefined
value convert to false , and any non-null object, array, or function converts to true .[/size]
number is 0 or NaN , which are converted to false . If a string is used where a boolean value is expected,
it is converted to true except for the empty string, which is converted to false . null and the undefined
value convert to false , and any non-null object, array, or function converts to true .[/size]
本文详细介绍了在编程中如何将数值类型(如整数、浮点数)、字符串、null及undefined等非布尔类型的值转换为布尔值的具体规则。文中提到,大多数情况下,非零数值会转换为true,而0和NaN则转换为false;对于字符串,除了空字符串以外的其他字符串均视为true;null和undefined值转换为false;而非空对象、数组和函数则一律转换为true。
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