Files

111 lines
4.2 KiB
JavaScript

const hexRegex = /^[-+]?0x[a-fA-F0-9]+$/;
const numRegex = /^([\-\+])?(0*)([0-9]*(\.[0-9]*)?)$/;
// const octRegex = /^0x[a-z0-9]+/;
// const binRegex = /0x[a-z0-9]+/;
const consider = {
hex : true,
// oct: false,
leadingZeros: true,
decimalPoint: "\.",
eNotation: true,
//skipLike: /regex/
};
function toNumber(str, options = {}){
options = Object.assign({}, consider, options );
if(!str || typeof str !== "string" ) return str;
let trimmedStr = str.trim();
if(options.skipLike !== undefined && options.skipLike.test(trimmedStr)) return str;
else if(str==="0") return 0;
else if (options.hex && hexRegex.test(trimmedStr)) {
return parse_int(trimmedStr, 16);
// }else if (options.oct && octRegex.test(str)) {
// return Number.parseInt(val, 8);
}else if (trimmedStr.search(/[eE]/)!== -1) { //eNotation
const notation = trimmedStr.match(/^([-\+])?(0*)([0-9]*(\.[0-9]*)?[eE][-\+]?[0-9]+)$/);
// +00.123 => [ , '+', '00', '.123', ..
if(notation){
// console.log(notation)
if(options.leadingZeros){ //accept with leading zeros
trimmedStr = (notation[1] || "") + notation[3];
}else{
if(notation[2] === "0" && notation[3][0]=== "."){ //valid number
}else{
return str;
}
}
return options.eNotation ? Number(trimmedStr) : str;
}else{
return str;
}
// }else if (options.parseBin && binRegex.test(str)) {
// return Number.parseInt(val, 2);
}else{
//separate negative sign, leading zeros, and rest number
const match = numRegex.exec(trimmedStr);
// +00.123 => [ , '+', '00', '.123', ..
if(match){
const sign = match[1];
const leadingZeros = match[2];
let numTrimmedByZeros = trimZeros(match[3]); //complete num without leading zeros
//trim ending zeros for floating number
if(!options.leadingZeros && leadingZeros.length > 0 && sign && trimmedStr[2] !== ".") return str; //-0123
else if(!options.leadingZeros && leadingZeros.length > 0 && !sign && trimmedStr[1] !== ".") return str; //0123
else if(options.leadingZeros && leadingZeros===str) return 0; //00
else{//no leading zeros or leading zeros are allowed
const num = Number(trimmedStr);
const numStr = "" + num;
if(numStr.search(/[eE]/) !== -1){ //given number is long and parsed to eNotation
if(options.eNotation) return num;
else return str;
}else if(trimmedStr.indexOf(".") !== -1){ //floating number
if(numStr === "0" && (numTrimmedByZeros === "") ) return num; //0.0
else if(numStr === numTrimmedByZeros) return num; //0.456. 0.79000
else if( sign && numStr === "-"+numTrimmedByZeros) return num;
else return str;
}
if(leadingZeros){
return (numTrimmedByZeros === numStr) || (sign+numTrimmedByZeros === numStr) ? num : str
}else {
return (trimmedStr === numStr) || (trimmedStr === sign+numStr) ? num : str
}
}
}else{ //non-numeric string
return str;
}
}
}
/**
*
* @param {string} numStr without leading zeros
* @returns
*/
function trimZeros(numStr){
if(numStr && numStr.indexOf(".") !== -1){//float
numStr = numStr.replace(/0+$/, ""); //remove ending zeros
if(numStr === ".") numStr = "0";
else if(numStr[0] === ".") numStr = "0"+numStr;
else if(numStr[numStr.length-1] === ".") numStr = numStr.substr(0,numStr.length-1);
return numStr;
}
return numStr;
}
function parse_int(numStr, base){
//polyfill
if(parseInt) return parseInt(numStr, base);
else if(Number.parseInt) return Number.parseInt(numStr, base);
else if(window && window.parseInt) return window.parseInt(numStr, base);
else throw new Error("parseInt, Number.parseInt, window.parseInt are not supported")
}
module.exports = toNumber;