它适用于字符和数字，通过可选步骤前进或后退。
var range = function(start, end, step) { var range = []; var typeofStart = typeof start; var typeofEnd = typeof end; if (step === 0) { throw TypeError("Step cannot be zero."); } if (typeofStart == "undefined" || typeofEnd == "undefined") { throw TypeError("Must pass start and end arguments."); } else if (typeofStart != typeofEnd) { throw TypeError("Start and end arguments must be of same type."); } typeof step == "undefined" && (step = 1); if (end < start) { step = -step; } if (typeofStart == "number") { while (step > 0 ? end >= start : end <= start) { range.push(start); start += step; } } else if (typeofStart == "string") { if (start.length != 1 || end.length != 1) { throw TypeError("only strings with one character are supported."); } start = start.charCodeAt(0); end = end.charCodeAt(0); while (step > 0 ? end >= start : end <= start) { range.push(String.fromCharCode(start)); start += step; } } else { throw TypeError("only string and number types are supported"); } return range;}jsFiddle。
如果您想扩展本机类型，则将其分配给
Array.range。
var range = function(start, end, step) { var range = []; var typeofStart = typeof start; var typeofEnd = typeof end; if (step === 0) { throw TypeError("Step cannot be zero."); } if (typeofStart == "undefined" || typeofEnd == "undefined") { throw TypeError("Must pass start and end arguments."); } else if (typeofStart != typeofEnd) { throw TypeError("Start and end arguments must be of same type."); } typeof step == "undefined" && (step = 1); if (end < start) { step = -step; } if (typeofStart == "number") { while (step > 0 ? end >= start : end <= start) { range.push(start); start += step; } } else if (typeofStart == "string") { if (start.length != 1 || end.length != 1) { throw TypeError("only strings with one character are supported."); } start = start.charCodeAt(0); end = end.charCodeAt(0); while (step > 0 ? end >= start : end <= start) { range.push(String.fromCharCode(start)); start += step; } } else { throw TypeError("only string and number types are supported"); } return range;}console.log(range("A", "Z", 1));console.log(range("Z", "A", 1));console.log(range("A", "Z", 3));console.log(range(0, 25, 1));console.log(range(0, 25, 5));console.log(range(20, 5, 5));
