66 lines
1.9 KiB
JavaScript
66 lines
1.9 KiB
JavaScript
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'use strict';
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const handlePreserveConsecutiveUppercase = (decamelized, separator) => {
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// Lowercase all single uppercase characters. As we
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// want to preserve uppercase sequences, we cannot
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// simply lowercase the separated string at the end.
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// `data_For_USACounties` → `data_for_USACounties`
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decamelized = decamelized.replace(
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/((?<![\p{Uppercase_Letter}\d])[\p{Uppercase_Letter}\d](?![\p{Uppercase_Letter}\d]))/gu,
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$0 => {
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return $0.toLowerCase();
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}
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);
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// Remaining uppercase sequences will be separated from lowercase sequences.
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// `data_For_USACounties` → `data_for_USA_counties`
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return decamelized.replace(
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/(\p{Uppercase_Letter}+)(\p{Uppercase_Letter}\p{Lowercase_Letter}+)/gu,
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(_, $1, $2) => {
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return $1 + separator + $2.toLowerCase();
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}
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);
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};
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module.exports = (
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text,
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{
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separator = '_',
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preserveConsecutiveUppercase = false
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} = {}
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) => {
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if (!(typeof text === 'string' && typeof separator === 'string')) {
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throw new TypeError(
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'The `text` and `separator` arguments should be of type `string`'
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);
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}
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// Checking the second character is done later on. Therefore process shorter strings here.
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if (text.length < 2) {
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return preserveConsecutiveUppercase ? text : text.toLowerCase();
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}
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const replacement = `$1${separator}$2`;
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// Split lowercase sequences followed by uppercase character.
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// `dataForUSACounties` → `data_For_USACounties`
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// `myURLstring → `my_URLstring`
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const decamelized = text.replace(
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/([\p{Lowercase_Letter}\d])(\p{Uppercase_Letter})/gu,
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replacement
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);
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if (preserveConsecutiveUppercase) {
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return handlePreserveConsecutiveUppercase(decamelized, separator);
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}
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// Split multiple uppercase characters followed by one or more lowercase characters.
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// `my_URLstring` → `my_url_string`
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return decamelized
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.replace(
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/(\p{Uppercase_Letter}+)(\p{Uppercase_Letter}\p{Lowercase_Letter}+)/gu,
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replacement
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)
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.toLowerCase();
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};
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