| 5 | |
| 6 | // Secure Math Parser (No Eval) |
| 7 | class MathParser { |
| 8 | constructor(str) { |
| 9 | this.tokens = this.tokenize(str); |
| 10 | this.pos = 0; |
| 11 | } |
| 12 | tokenize(str) { |
| 13 | return ( |
| 14 | str |
| 15 | .replace(/\s+/g, "") |
| 16 | .match(/([0-9]*\.?[0-9]+|[a-z]+|[+\-*/^()]|x)/gi) || [] |
| 17 | ); |
| 18 | } |
| 19 | consume() { |
| 20 | return this.tokens[this.pos++]; |
| 21 | } |
| 22 | peek() { |
| 23 | return this.tokens[this.pos]; |
| 24 | } |
| 25 | parseExpression() { |
| 26 | let node = this.parseTerm(); |
| 27 | while (this.peek() === "+" || this.peek() === "-") { |
| 28 | const op = this.consume(); |
| 29 | const right = this.parseTerm(); |
| 30 | const left = node; |
| 31 | node = (x) => |
| 32 | op === "+" ? left(x) + right(x) : left(x) - right(x); |
| 33 | } |
| 34 | return node; |
| 35 | } |
| 36 | parseTerm() { |
| 37 | let node = this.parsePower(); |
| 38 | while (this.peek() === "*" || this.peek() === "/") { |
| 39 | const op = this.consume(); |
| 40 | const right = this.parsePower(); |
| 41 | const left = node; |
| 42 | node = (x) => { |
| 43 | const r = right(x); |
| 44 | return op === "*" ? left(x) * r : r === 0 ? NaN : left(x) / r; |
| 45 | }; |
| 46 | } |
| 47 | return node; |
| 48 | } |
| 49 | parsePower() { |
| 50 | let node = this.parseFactor(); |
| 51 | while (this.peek() === "^") { |
| 52 | this.consume(); |
| 53 | const right = this.parseFactor(); |
| 54 | const left = node; |
| 55 | node = (x) => Math.pow(left(x), right(x)); |
| 56 | } |
| 57 | return node; |
| 58 | } |
| 59 | parseFactor() { |
| 60 | const token = this.consume(); |
| 61 | if (token === "(") { |
| 62 | const node = this.parseExpression(); |
| 63 | this.consume(); |
| 64 | return node; |
nothing calls this directly
no outgoing calls
no test coverage detected