17 lines
433 B
Java
17 lines
433 B
Java
var toValString = require('./toString')
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/**
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* 判断字符串是否在源字符串的头部
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*
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* @param {String} str 字符串
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* @param {String/Number} val 值
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* @param {Number} startIndex 开始索引
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* @return {String}
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*/
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function startsWith (str, val, startIndex) {
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var rest = toValString(str)
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return (arguments.length === 1 ? rest : rest.substring(startIndex)).indexOf(val) === 0
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}
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module.exports = startsWith
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