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							- import assertString from './util/assertString';
 
- var defaultOptions = {
 
-   loose: false
 
- };
 
- var strictBooleans = ['true', 'false', '1', '0'];
 
- var looseBooleans = [].concat(strictBooleans, ['yes', 'no']);
 
- export default function isBoolean(str) {
 
-   var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : defaultOptions;
 
-   assertString(str);
 
-   if (options.loose) {
 
-     return looseBooleans.includes(str.toLowerCase());
 
-   }
 
-   return strictBooleans.includes(str);
 
- }
 
 
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