--- id: 5d792534d586ef495ea9df90 title: Part 28 challengeType: 0 isHidden: true --- ## Description <section id='description'> Set `str2` to `infixEval(noHigh, infix)`. </section> ## Instructions <section id='instructions'> </section> ## Tests <section id='tests'> ```yml tests: - text: See description above for instructions. testString: assert(code.replace(/\s/g, "").includes("constapplyFn=str=>{constnoHigh=highPrecedence(str);constinfix=/([0-9.]+)([+-])([0-9.]+)/;conststr2=infixEval(noHigh,infix)")); ``` </section> ## Challenge Seed <section id='challengeSeed'> <div id='html-seed'> ```html <script> const infixToFunction = { "+": (x, y) => x + y, "-": (x, y) => x - y, "*": (x, y) => x * y, "/": (x, y) => x / y }; const infixEval = (str, regex) => str.replace(regex, (_, arg1, fn, arg2) => infixToFunction[fn](parseFloat(arg1), parseFloat(arg2)) ); const highPrecedence = str => { const regex = /([0-9.]+)([*\/])([0-9.]+)/; const str2 = infixEval(str, regex); return str === str2 ? str : highPrecedence(str2); }; const spreadsheetFunctions = { "": x => x }; const applyFn = str => { const noHigh = highPrecedence(str); const infix = /([0-9.]+)([+-])([0-9.]+)/; } </script> ``` </div> ### Before Test <div id='html-setup'> ```html <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Spreadsheet</title> <style> #container { display: grid; grid-template-columns: 50px repeat(10, 200px); grid-template-rows: repeat(11, 30px); } .label { background-color: lightgray; text-align: center; vertical-align: middle; line-height: 30px; } </style> </head> <body> <div id="container"> <div></div> </div> ``` </div> ### After Test <div id='html-teardown'> ```html </body> </html> ``` </div> </section> ## Solution <section id='solution'> ```html <script> const infixToFunction = { "+": (x, y) => x + y, "-": (x, y) => x - y, "*": (x, y) => x * y, "/": (x, y) => x / y }; const infixEval = (str, regex) => str.replace(regex, (_, arg1, fn, arg2) => infixToFunction[fn](parseFloat(arg1), parseFloat(arg2)) ); const highPrecedence = str => { const regex = /([0-9.]+)([*\/])([0-9.]+)/; const str2 = infixEval(str, regex); return str === str2 ? str : highPrecedence(str2); }; const spreadsheetFunctions = { "": x => x }; const applyFn = str => { const noHigh = highPrecedence(str); const infix = /([0-9.]+)([+-])([0-9.]+)/; const str2 = infixEval(noHigh, infix); } </script> ``` </section>