1  'use strict';
 2  
 3  const preserveCamelCase = string => {
 4  	let isLastCharLower = false;
 5  	let isLastCharUpper = false;
 6  	let isLastLastCharUpper = false;
 7  
 8  	for (let i = 0; i < string.length; i++) {
 9  		const character = string[i];
10  
11  		if (isLastCharLower && /[a-zA-Z]/.test(character) && character.toUpperCase() === character) {
12  			string = string.slice(0, i) + '-' + string.slice(i);
13  			isLastCharLower = false;
14  			isLastLastCharUpper = isLastCharUpper;
15  			isLastCharUpper = true;
16  			i++;
17  		} else if (isLastCharUpper && isLastLastCharUpper && /[a-zA-Z]/.test(character) && character.toLowerCase() === character) {
18  			string = string.slice(0, i - 1) + '-' + string.slice(i - 1);
19  			isLastLastCharUpper = isLastCharUpper;
20  			isLastCharUpper = false;
21  			isLastCharLower = true;
22  		} else {
23  			isLastCharLower = character.toLowerCase() === character && character.toUpperCase() !== character;
24  			isLastLastCharUpper = isLastCharUpper;
25  			isLastCharUpper = character.toUpperCase() === character && character.toLowerCase() !== character;
26  		}
27  	}
28  
29  	return string;
30  };
31  
32  const camelCase = (input, options) => {
33  	if (!(typeof input === 'string' || Array.isArray(input))) {
34  		throw new TypeError('Expected the input to be `string | string[]`');
35  	}
36  
37  	options = Object.assign({
38  		pascalCase: false
39  	}, options);
40  
41  	const postProcess = x => options.pascalCase ? x.charAt(0).toUpperCase() + x.slice(1) : x;
42  
43  	if (Array.isArray(input)) {
44  		input = input.map(x => x.trim())
45  			.filter(x => x.length)
46  			.join('-');
47  	} else {
48  		input = input.trim();
49  	}
50  
51  	if (input.length === 0) {
52  		return '';
53  	}
54  
55  	if (input.length === 1) {
56  		return options.pascalCase ? input.toUpperCase() : input.toLowerCase();
57  	}
58  
59  	const hasUpperCase = input !== input.toLowerCase();
60  
61  	if (hasUpperCase) {
62  		input = preserveCamelCase(input);
63  	}
64  
65  	input = input
66  		.replace(/^[_.\- ]+/, '')
67  		.toLowerCase()
68  		.replace(/[_.\- ]+(\w|$)/g, (_, p1) => p1.toUpperCase())
69  		.replace(/\d+(\w|$)/g, m => m.toUpperCase());
70  
71  	return postProcess(input);
72  };
73  
74  module.exports = camelCase;
75  // TODO: Remove this for the next major release
76  module.exports.default = camelCase;