Fix towei scientific notation

packages/web3-utils/CHANGELOG.md

@@ -213,7 +213,15 @@ Documentation:
 
 ### Fixed
 
--   fixed toHex incorrectly hexing Uint8Arrays and Buffer (#6957)
--   fixed isUint8Array not returning true for Buffer (#6957)
+- fixed toHex incorrectly hexing Uint8Arrays and Buffer (#6957)
+- fixed isUint8Array not returning true for Buffer (#6957)
 
 ## [Unreleased]
+
+### Added
+
+- `toWei` add warning when using large numbers or large decimals that may cause precision loss (#6908)
+
+### Fixed
+
+- `toWei` support numbers in scientific notation (#6908)

packages/web3-utils/src/converters.ts

@@ -77,6 +77,8 @@ export const ethUnitMap = {
 	tether: BigInt('1000000000000000000000000000000'),
 };
 
+const PrecisionLossWarning = 'Warning: Using type `number` with values that are large or contain many decimals may cause loss of precision, it is recommended to use type `string` or `BigInt` when using conversion methods';
+
 export type EtherUnits = keyof typeof ethUnitMap;
 /**
  * Convert a value from bytes to Uint8Array
@@ -415,7 +417,8 @@ export const toHex = (
  */
 export const toNumber = (value: Numbers): number | bigint => {
 	if (typeof value === 'number') {
-            if (value > 1e+20) {
+			if (value > 1e+20) {
+				console.warn(PrecisionLossWarning)
                 // JavaScript converts numbers >= 10^21 to scientific notation when coerced to strings,
                 // leading to potential parsing errors and incorrect representations.
                 // For instance, String(10000000000000000000000) yields '1e+22'.
@@ -555,17 +558,32 @@ export const toWei = (number: Numbers, unit: EtherUnits): string => {
 	if (!denomination) {
 		throw new InvalidUnitError(unit);
 	}
+	let parsedNumber = number;
+	if (typeof parsedNumber === 'number'){
+		if (parsedNumber  < 1e-15){
+			console.warn(PrecisionLossWarning)
+		}
+		if (parsedNumber > 1e+20) {
+			console.warn(PrecisionLossWarning)
 
+			parsedNumber =  BigInt(parsedNumber);
+		} else {
+			// in case there is a decimal point, we need to convert it to string
+			parsedNumber = parsedNumber.toLocaleString('fullwide', {useGrouping: false, maximumFractionDigits: 20})
+		}
+	}
+
 	// if value is decimal e.g. 24.56 extract `integer` and `fraction` part
 	// to avoid `fraction` to be null use `concat` with empty string
 	const [integer, fraction] = String(
-		typeof number === 'string' && !isHexStrict(number) ? number : toNumber(number),
+		typeof parsedNumber === 'string' && !isHexStrict(parsedNumber) ? parsedNumber : toNumber(parsedNumber),
 	)
 		.split('.')
 		.concat('');
 
 	// join the value removing `.` from
 	// 24.56 -> 2456
+
 	const value = BigInt(`${integer}${fraction}`);
 
 	// multiply value with denomination

packages/web3-utils/test/fixtures/converters.ts

@@ -300,9 +300,20 @@ export const fromWeiValidData: [[Numbers, EtherUnits], string][] = [
     [[1.9999999999999991611392e+22, 'ether'], '19999.999999999991611392'],
 ];
 
-export const toWeiValidData: [[Numbers, EtherUnits], string][] = [
+export const toWeiValidData: [[Numbers, EtherUnits], Numbers][] = [
 	...conversionBaseData,
 	[['255', 'wei'], '0xFF'],
+	[['100000000000', 'ether'], 0.0000001],
+	[['1000000000', 'ether'], 0.000000001],
+	[['1000000', 'ether'], 0.000000000001]
+
+];
+
+export const toWeiValidDataWarnings: [[Numbers, EtherUnits], string][] = [
+	[[0.0000000000000000000001, 'ether'], 'Warning: Using type `number` with values that are large or contain many decimals may cause loss of precision, it is recommended to use type `string` or `BigInt` when using conversion methods'],
+	[[0.0000000000000000000001, 'ether'], 'Warning: Using type `number` with values that are large or contain many decimals may cause loss of precision, it is recommended to use type `string` or `BigInt` when using conversion methods'],
+	[[1999999000000009900000, 'kwei'], 'Warning: Using type `number` with values that are large or contain many decimals may cause loss of precision, it is recommended to use type `string` or `BigInt` when using conversion methods'],
+
 ];
 
 export const fromWeiInvalidData: [[any, any], string][] = [

packages/web3-utils/test/unit/converters.test.ts

@@ -63,6 +63,7 @@ import {
 	toHexInvalidData,
 	toWeiInvalidData,
 	toWeiValidData,
+	toWeiValidDataWarnings,
 	utf8ToHexInvalidData,
 	utf8ToHexValidData,
 	toCheckSumValidData,
@@ -365,6 +366,19 @@ describe('converters', () => {
 				expect(() => toWei(input[0], input[1])).toThrow(output);
 			});
 		});
+		describe('test console warnings', () => {
+			beforeEach(() => {
+				jest.spyOn(console, 'warn').mockImplementation(() => {
+					// do nothing
+				});
+			});
+			it.each(toWeiValidDataWarnings)('%s', (input, output) => {
+				toWei(input[0], input[1]);
+				// expect(() => toWei(input[0], input[1])).toThrow(output);
+				expect(console.warn).toHaveBeenCalledWith(output)
+			});
+
+		})
 	});
 	describe('toChecksumAddress', () => {
 		describe('valid cases', () => {