@haz3y0ne/parsexl/dist/parseFormula.js

Parses Excel formulas into a clean, well-typed abstract syntax tree you can analyse or evaluate in TypeScript.

// parseFormula.ts
import { tokenize } from "./lexer";
import { collapseBinary, normalizeFilters } from "./transforms";
import { parseTokensPratt } from "./parser";
/**
 * Convert an Excel-style formula into a fully-post-processed AST:
 * ──────────────────────────────────────────────────────────────
 * 1.  Minify the input             → drop the leading “=” and *every* whitespace
 *                                    (new-lines, tabs, spaces, CRs).
 * 2.  Tokenise                     → longest-match scan.
 * 3.  Pratt parse                  → precedence & parentheses.
 * 4.  Post-passes                  → collapseBinary, normalizeFilters.
 * 5.  Prune                        → delete `args` arrays that ended up empty
 *                                    to keep the JSON lean.
 */
export function parseFormula(formula, devMode) {
    /* ── 1  whitespace / “=” ─────────────────────────────────────────────── */
    const cleaned = formula
        .trim() // leading / trailing
        .replace(/^=/, "") // Excel’s mandatory “=”
        .replace(/\s+/g, ""); // every remaining whitespace char
    /* ── 2  lex ──────────────────────────────────────────────────────────── */
    const rawTokens = tokenize(cleaned, devMode);
    /* ── 3  Pratt parse ──────────────────────────────────────────────────── */
    const ast = parseTokensPratt(rawTokens);
    /* ── 4  post-process ─────────────────────────────────────────────────── */
    collapseBinary(ast);
    normalizeFilters(ast);
    /* ── 5  prune empty arg arrays ───────────────────────────────────────── */
    pruneEmptyArgs(ast);
    return ast;
}
/* ---------------------------------------------------------------------- */
/*  Helper: recursively delete args: [] to keep output compact            */
/* ---------------------------------------------------------------------- */
function pruneEmptyArgs(node) {
    if (node.args.length === 0) {
        // remove the property entirely
        // (TS ignores extra runtime keys, so this is safe)
        // eslint-disable-next-line @typescript-eslint/ban-ts-comment
        // @ts-ignore
        delete node.args;
        return;
    }
    for (const child of node.args)
        pruneEmptyArgs(child);
}