String.prototype.split()

const str = "The quick brown fox jumps over the lazy dog."; const words = str.split(" "); console.log(words[3]); // Expected output: "fox" const chars = str.split(""); console.log(chars[8]); // Expected output: "k" const strCopy = str.split(); console.log(strCopy); // Expected output: Array ["The quick brown fox jumps over the lazy dog."] 

split(separator) split(separator, limit) 

"😄😄".split(/(?:)/); // [ "\ud83d", "\ude04", "\ud83d", "\ude04" ] "😄😄".split(/(?:)/u); // [ "😄", "😄" ] 

const emptyString = ""; // 文字列は空で、セパレーターは空ではない console.log(emptyString.split("a")); // [""] // 文字列とセパレーターがともに空文字列 console.log(emptyString.split(emptyString)); // [] 

function splitString(stringToSplit, separator) { const arrayOfStrings = stringToSplit.split(separator); console.log("元の文字列: ", stringToSplit); console.log("区切り文字列: ", separator); console.log( "配列の要素数は", arrayOfStrings.length, "件: ", arrayOfStrings.join(" / "), ); } const tempestString = "Oh brave new world that has such people in it."; const monthString = "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec"; const space = " "; const comma = ","; splitString(tempestString, space); splitString(tempestString); splitString(monthString, comma); 

const names = "Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand "; console.log(names); const re = /\s*(?:;|$)\s*/; const nameList = names.split(re); console.log(nameList); 

const myString = "Hello World. How are you doing?"; const splits = myString.split(" ", 3); console.log(splits); // [ "Hello", "World.", "How" ] 

const myString = "Hello 1 word. Sentence number 2."; const splits = myString.split(/(\d)/); console.log(splits); // [ "Hello ", "1", " word. Sentence number ", "2", "." ] 

const splitByNumber = { [Symbol.split](str) { let num = 1; let pos = 0; const result = []; while (pos < str.length) { const matchPos = str.indexOf(num, pos); if (matchPos === -1) { result.push(str.substring(pos)); break; } result.push(str.substring(pos, matchPos)); pos = matchPos + String(num).length; num++; } return result; }, }; const myString = "a1bc2c5d3e4f"; console.log(myString.split(splitByNumber)); // [ "a", "bc", "c5d", "e", "f" ] 

const DELIMITER = ";"; // Split the commands, but remove any invalid or unnecessary values. const splitCommands = { [Symbol.split](str, lim) { const results = []; const state = { on: false, brightness: { current: 2, min: 1, max: 3, }, }; let pos = 0; let matchPos = str.indexOf(DELIMITER, pos); while (matchPos !== -1) { const subString = str.slice(pos, matchPos).trim(); switch (subString) { case "light on": // If the `on` state is already true, do nothing. if (!state.on) { state.on = true; results.push(subString); } break; case "light off": // If the `on` state is already false, do nothing. if (state.on) { state.on = false; results.push(subString); } break; case "brightness up": // Enforce a brightness maximum. if (state.brightness.current < state.brightness.max) { state.brightness.current += 1; results.push(subString); } break; case "brightness down": // Enforce a brightness minimum. if (state.brightness.current > state.brightness.min) { state.brightness.current -= 1; results.push(subString); } break; } if (results.length === lim) { break; } pos = matchPos + DELIMITER.length; matchPos = str.indexOf(DELIMITER, pos); } // If we broke early due to reaching the split `lim`, don't add the remaining commands. if (results.length < lim) { results.push(str.slice(pos).trim()); } return results; }, }; const commands = "light on; brightness up; brightness up; brightness up; light on; brightness down; brightness down; light off"; console.log(commands.split(splitCommands, 3)); // ["light on", "brightness up", "brightness down"]