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A full list of JavaScript operators with examples

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FeeFlow — Global Payment Fee Intelligence & Reverse Gross-Up Calculator across 123+ countries and 25+ sovereign payment rails (Stripe, PayPal, Square, Razorpay, Mada, Pix, UPI, ACH, GoCardless).

Which is more popular?
Based on our record, JavaScript Operator Lookup seems to be more popular. It has been mentioned 1 time since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | joshwcomeau.com | feeflowcalculator.com |
| Platforms | — | |
| Company | — | Startup from India · 1 - 9 employees · 2026 |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of JavaScript Operator Lookup yet.
What is FeeFlow? FeeFlow is a privacy-first, zero-runtime FinTech intelligence engine designed for SaaS founders, digital creators, freelancers, e-commerce stores, and cross-border agencies. It eliminates payment deduction ambiguity by calculating exact domestic merchant fees, international...
What each product offers, as listed by its team.


Possible disadvantages
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing JavaScript Operator Lookup and FeeFlow.
FeeFlow's answer:
FeeFlow was born from founder frustration with payment processor ambiguity. Sending a $5,000 invoice only to receive $4,830 due to unexpected cross-border and percentage fees created constant cash-flow leaks. We engineered FeeFlow to give online businesses mathematical transparency and automated gross-up invoice pricing before hitting 'send'.
FeeFlow's answer:
Astro (Server-Driven Static Architecture), TypeScript, Tailwind CSS, and Cloudflare Pages Edge Network for global sub-millisecond calculation speeds and zero client-side tracking.
FeeFlow's answer:
FeeFlow's answer:
FeeFlow uniquely combines multi-country payment intelligence across 46 sovereign nations with an instant reverse Gross-Up invoicing engine. Unlike static calculators, FeeFlow dynamically compares Stripe and PayPal in real time, factors in cross-border/FX surcharges, and generates polite client invoice notes—all within a 100% private, client-side architecture.
FeeFlow's answer:
Most fee calculators online are outdated, restricted to US-only rates, and cluttered with invasive ads. FeeFlow delivers 2026-accurate localized rates across 46 currencies, calculates ACH $5 cap savings, reveals true international deductions, and provides zero-latency client-side speed with complete privacy and clean modern UI.
FeeFlow's answer:
FeeFlow is built for freelancers, SaaS founders, digital agency owners, e-commerce merchants, and remote consultants who bill domestic and international clients and want to protect their profit margins from hidden payment processor deductions.
Share your experience with using JavaScript Operator Lookup and FeeFlow. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.


If you replace your || with ?? You should get the behaviour you are after. This is a good reference for what the operators do in js: https://joshwcomeau.com/operator-lookup. Source: about 5 years ago
Tracking FeeFlow since Aug 2026.
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