fix: every balance is cut to four decimals (closes #757)

The balance lists and Home's ETH line rounded with toFixed(4), so 0.99996
ETH read 1.0000 there and 0.9999 on Send. Send's current balance and
ConfirmTx's balance line kept the nonzero floor, so 0.00004 USDC read
0.0000 in the lists and 0.00004 on Send. All four now cut the stored
decimal string with truncateAmount(), as the history rows do.
balanceLine() takes the stored balance string instead of a parsed number,
and escapes the quantity cell. The amounts, fees and allowances a screen
asks the user to approve keep the floor of truncateAmountNeverZero().

Model: opus-5-5

src/popup/views/addressToken.js

@@ -159,10 +159,10 @@ function renderBalance() {
     const addr =
         state.wallets[state.selectedWallet].addresses[state.selectedAddress];
     const tokenId = state.selectedToken;
-    let amount, price;
+    let balance, price;
     if (tokenId === "ETH") {
         // null when no refresh has read the balance.
-        amount = unknownableAmount(addr.balance);
+        balance = addr.balance;
         price = getPrice("ETH");
     } else {
         const id = tokenId.toLowerCase();
@@ -175,12 +175,13 @@ function renderBalance() {
         // null when the scale is unknown, or when no refresh has read the
         // token's balance: no quantity to show, and none to price.
         // balanceLine() states that rather than printing 0.0000.
-        if (tb) amount = unknownableAmount(tb.balance);
-        else amount = tracked && tracked.balanceNotFetched ? null : 0;
+        if (tb) balance = tb.balance;
+        else balance = tracked && tracked.balanceNotFetched ? null : "0";
         price = getPrice(tokenId);
     }
 
     // USD total for this token only
+    const amount = unknownableAmount(balance);
     const usdVal = price && amount !== null ? amount * price : null;
     const usdStr = formatUsd(usdVal);
     $("address-token-usd-total").innerHTML = escapeHtml(usdStr) || " ";
@@ -188,7 +189,7 @@ function renderBalance() {
     // Single token balance line (no tokenId — not clickable here)
     $("address-token-balance").innerHTML = balanceLine(
         currentSymbol,
-        amount,
+        balance,
         price,
     );
 }

src/popup/views/confirmTx.js

@@ -43,9 +43,12 @@ const {
     transferAmountUnits,
 } = require("../../shared/transferAmount");
 const { assertWithinCeilings } = require("../../shared/approvalVerify");
-// The amount, the balance line and the fee reserve go through it, as the
-// approval screen's amounts do.
-const { truncateAmountNeverZero } = require("../../shared/amountDisplay");
+// The amount and the fee reserve keep the nonzero floor, as the approval
+// screen's amounts do. The balance line is cut as the balance lists cut it.
+const {
+    truncateAmount,
+    truncateAmountNeverZero,
+} = require("../../shared/amountDisplay");
 const {
     CODES,
     FEE_PENDING,
@@ -160,7 +163,7 @@ function renderBalance(txInfo) {
     const price = getPrice(txInfo.token, txInfo.chainId);
     const balUsd = price ? parseFloat(bal) * price : null;
     $("confirm-balance").textContent = valueWithUsd(
-        truncateAmountNeverZero(bal) + " " + symbol,
+        truncateAmount(bal) + " " + symbol,
         balUsd,
     );
 }

src/popup/views/deleteAddress.js

@@ -79,8 +79,8 @@ function recoveryPathText(wallet) {
 // "Holds" means ETH or any ERC-20 the wallet knows about — an address with no
 // ETH and a five-figure stablecoin position must not get the blank line on
 // the one screen whose job is to warn. The sentence names no figure of its
-// own: the rendered lines round to four decimals, so a sentence built from a
-// rounded number would report "0.0000 ETH" for an address holding real money.
+// own: the rendered lines cut to four decimals, so a sentence built from their
+// figure would report "0.0000 ETH" for an address holding real money.
 // The lines below it carry the amounts, in the same format as Home and
 // AddressDetail, followed by the USD total when there is one to give — no
 // total line at all on testnet, before the first price fetch or while no

src/popup/views/helpers.js

@@ -18,6 +18,7 @@
 const { formatEther } = require("ethers");
 const makeBlockie = require("ethereum-blockies-base64");
 const {
+    truncateAmount,
     truncateAmountNeverZero,
     isBelowOneMillionth,
 } = require("../../shared/amountDisplay");
@@ -373,13 +374,15 @@ function formatFee(wei, symbol, chainId) {
 // the row that issue #307 was reported against: every screen that lists a
 // holding renders through here.
 //
-// `amount` is null for a holding whose scale nothing knows
+// `balance` is the stored balance, a decimal string. It is null for a holding
+// whose scale nothing knows
 // (https://git.eeqj.de/sneak/AutistMask/issues/349), and for a balance no
 // refresh has read. There is no quantity to print for it and no fiat value to
-// derive from one, and printing 0.0000 for a real holding is the failure this
-// whole rule exists to prevent, so the row says so instead.
-function balanceLine(symbol, amount, price, tokenId) {
-    const qty = amount === null ? "quantity unknown" : amount.toFixed(4);
+// derive from one. A holding whose amount is unknown is shown as
+// `quantity unknown` rather than as a zero.
+function balanceLine(symbol, balance, price, tokenId) {
+    const amount = unknownableAmount(balance);
+    const qty = amount === null ? "quantity unknown" : truncateAmount(balance);
     const usd =
         price && amount !== null
             ? escapeHtml(formatUsd(amount * price)) || " "
@@ -394,7 +397,7 @@ function balanceLine(symbol, amount, price, tokenId) {
         `<div class="flex text-xs${clickClass}"${tokenAttr}>` +
         `<span class="flex justify-between w-[42ch] max-w-full">` +
         `<span>${escapeHtml(displaySymbol(symbol))}</span>` +
-        `<span>${qty}</span>` +
+        `<span>${escapeHtml(qty)}</span>` +
         `</span>` +
         `<span class="text-right text-muted flex-1">${usd}</span>` +
         `</div>`
@@ -420,7 +423,7 @@ function markTrackedTokensNotFetched() {
 function balanceLinesForAddress(addr, trackedTokens, showZero) {
     let html = balanceLine(
         nativeCurrency(),
-        unknownableAmount(addr.balance),
+        addr.balance,
         getPrice("ETH"),
         "ETH",
     );
@@ -438,7 +441,7 @@ function balanceLinesForAddress(addr, trackedTokens, showZero) {
         if (bal === 0 && !showZero) continue;
         html += balanceLine(
             t.symbol,
-            bal,
+            t.balance,
             getPrice(t.address),
             t.address.toLowerCase(),
         );
@@ -456,7 +459,7 @@ function balanceLinesForAddress(addr, trackedTokens, showZero) {
             }
             html += balanceLine(
                 t.symbol,
-                t.balanceNotFetched ? null : 0,
+                t.balanceNotFetched ? null : "0",
                 getPrice(t.address),
                 t.address.toLowerCase(),
             );
@@ -467,10 +470,10 @@ function balanceLinesForAddress(addr, trackedTokens, showZero) {
 
 // Whether an address holds anything at all: ETH or any ERC-20 the wallet
 // knows about, except a token holding below 0.000001, which the balance list
-// under the remove-address warning leaves out too. Deliberately unrounded —
-// the rendered lines round to four decimals, so a dust balance displays as
-// 0.0000 while still being real money at a real address. Callers that warn
-// about holdings must ask this, not the rendered figure.
+// under the remove-address warning leaves out too. Deliberately exact — the
+// rendered lines cut to four decimals, so a dust balance displays as 0.0000
+// while still being real money at a real address. Callers that warn about
+// holdings must ask this, not the rendered figure.
 function addressHoldsFunds(addr) {
     if (!addr) return false;
     // A null or absent ETH balance reads as unknown, so the address may hold

src/popup/views/home.js

@@ -31,6 +31,7 @@ const {
     resetSendValidation,
 } = require("./send");
 const { deriveAddressFromXpub } = require("../../shared/wallet");
+const { truncateAmount } = require("../../shared/amountDisplay");
 const { canRemoveAddress } = require("../../shared/walletDelete");
 const {
     walletDefect,
@@ -81,7 +82,7 @@ function renderTotalValue() {
     if (ethBal === null) {
         el.textContent = "unknown (" + nativeCurrency() + ")";
     } else {
-        const ethStr = ethBal.toFixed(4) + " " + nativeCurrency();
+        const ethStr = truncateAmount(addr.balance) + " " + nativeCurrency();
         const ethUsd = ethPrice
             ? " (" + formatUsd(ethBal * ethPrice) + ")"
             : "";

src/popup/views/send.js

@@ -24,7 +24,7 @@ const { resolveSymbol } = require("../../shared/tokenList");
 const { isLowHolderCount } = require("../../shared/holders");
 const { isSpoofedSymbol } = require("../../shared/symbolSpoof");
 const {
-    truncateAmountNeverZero,
+    truncateAmount,
     isBelowOneMillionth,
 } = require("../../shared/amountDisplay");
 const {
@@ -239,7 +239,7 @@ function updateSendBalance() {
             addr.balance == null
                 ? "Current balance: unknown (" + nativeCurrency() + ")"
                 : "Current balance: " +
-                  truncateAmountNeverZero(addr.balance) +
+                  truncateAmount(addr.balance) +
                   " " +
                   nativeCurrency();
     } else {
@@ -258,18 +258,15 @@ function updateSendBalance() {
         $("send-balance").textContent =
             bal == null
                 ? "Current balance: unknown (" + symbol + ")"
-                : "Current balance: " +
-                  truncateAmountNeverZero(bal) +
-                  " " +
-                  symbol;
+                : "Current balance: " + truncateAmount(bal) + " " + symbol;
     }
 }
 
 // Fill the amount field with the most the selected holding can send: a
 // token's whole balance (cut to 18 decimal places), or for ETH the exact
 // balance minus the fee reserve the confirmation screen checks against, never
-// the rounded balance the screen shows. Where there is nothing to fill in, a
-// flash message says why.
+// the balance the screen shows, which is cut to four decimals. Where there is
+// nothing to fill in, a flash message says why.
 async function fillMaxAmount() {
     const addr = currentAddress();
     if (!addr) return;