22 lines
556 B
JavaScript
22 lines
556 B
JavaScript
var utils = require('../utils')
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, nodes = require('../nodes');
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/**
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* Returns substring of the given `val`.
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*
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* @param {String|Ident} val
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* @param {Number} start
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* @param {Number} [length]
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* @return {String|Ident}
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* @api public
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*/
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module.exports = function substr(val, start, length){
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utils.assertString(val, 'val');
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utils.assertType(start, 'unit', 'start');
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length = length && length.val;
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var res = val.string.substr(start.val, length);
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return val instanceof nodes.Ident
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? new nodes.Ident(res)
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: new nodes.String(res);
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};
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