v1.0 with SW PWA enabled

frontend/node_modules/eslint/lib/rules/no-loss-of-precision.js

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+/**
+ * @fileoverview Rule to flag numbers that will lose significant figure precision at runtime
+ * @author Jacob Moore
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/** Class representing a number in scientific notation. */
+class ScientificNotation {
+	/** @type {string} The digits of the coefficient. A decimal point is implied after the first digit. */
+	coefficient;
+
+	/** @type {number} The order of magnitude. */
+	magnitude;
+
+	constructor(coefficient, magnitude) {
+		this.coefficient = coefficient;
+		this.magnitude = magnitude;
+	}
+
+	/* c8 ignore start -- debug only */
+	toString() {
+		return `${this.coefficient[0]}${this.coefficient.length > 1 ? `.${this.coefficient.slice(1)}` : ""}e${this.magnitude}`;
+	}
+	/* c8 ignore stop */
+}
+
+/**
+ * Returns whether the node is number literal
+ * @param {Node} node the node literal being evaluated
+ * @returns {boolean} true if the node is a number literal
+ */
+function isNumber(node) {
+	return typeof node.value === "number";
+}
+
+/**
+ * Gets the source code of the given number literal. Removes `_` numeric separators from the result.
+ * @param {Node} node the number `Literal` node
+ * @returns {string} raw source code of the literal, without numeric separators
+ */
+function getRaw(node) {
+	return node.raw.replace(/_/gu, "");
+}
+
+/**
+ * Checks whether the number is base ten
+ * @param {ASTNode} node the node being evaluated
+ * @returns {boolean} true if the node is in base ten
+ */
+function isBaseTen(node) {
+	const prefixes = ["0x", "0X", "0b", "0B", "0o", "0O"];
+
+	return (
+		prefixes.every(prefix => !node.raw.startsWith(prefix)) &&
+		!/^0[0-7]+$/u.test(node.raw)
+	);
+}
+
+/**
+ * Checks that the user-intended non-base ten number equals the actual number after is has been converted to the Number type
+ * @param {Node} node the node being evaluated
+ * @returns {boolean} true if they do not match
+ */
+function notBaseTenLosesPrecision(node) {
+	const rawString = getRaw(node).toUpperCase();
+	let base;
+
+	if (rawString.startsWith("0B")) {
+		base = 2;
+	} else if (rawString.startsWith("0X")) {
+		base = 16;
+	} else {
+		base = 8;
+	}
+
+	return !rawString.endsWith(node.value.toString(base).toUpperCase());
+}
+
+/**
+ * Returns the number stripped of leading zeros
+ * @param {string} numberAsString the string representation of the number
+ * @returns {string} the stripped string
+ */
+function removeLeadingZeros(numberAsString) {
+	for (let i = 0; i < numberAsString.length; i++) {
+		if (numberAsString[i] !== "0") {
+			return numberAsString.slice(i);
+		}
+	}
+	return numberAsString;
+}
+
+/**
+ * Returns the number stripped of trailing zeros
+ * @param {string} numberAsString the string representation of the number
+ * @returns {string} the stripped string
+ */
+function removeTrailingZeros(numberAsString) {
+	for (let i = numberAsString.length - 1; i >= 0; i--) {
+		if (numberAsString[i] !== "0") {
+			return numberAsString.slice(0, i + 1);
+		}
+	}
+	return numberAsString;
+}
+
+/**
+ * Converts an integer to an object containing the integer's coefficient and order of magnitude
+ * @param {string} stringInteger the string representation of the integer being converted
+ * @returns {ScientificNotation} the object containing the integer's coefficient and order of magnitude
+ */
+function normalizeInteger(stringInteger) {
+	const trimmedInteger = removeLeadingZeros(stringInteger);
+	const significantDigits = removeTrailingZeros(trimmedInteger);
+
+	return new ScientificNotation(significantDigits, trimmedInteger.length - 1);
+}
+
+/**
+ * Converts a float to an object containing the float's coefficient and order of magnitude
+ * @param {string} stringFloat the string representation of the float being converted
+ * @returns {ScientificNotation} the object containing the float's coefficient and order of magnitude
+ */
+function normalizeFloat(stringFloat) {
+	const trimmedFloat = removeLeadingZeros(stringFloat);
+	const indexOfDecimalPoint = trimmedFloat.indexOf(".");
+
+	switch (indexOfDecimalPoint) {
+		case 0: {
+			const significantDigits = removeLeadingZeros(trimmedFloat.slice(1));
+
+			return new ScientificNotation(
+				significantDigits,
+				significantDigits.length - trimmedFloat.length,
+			);
+		}
+		case -1:
+			return new ScientificNotation(
+				trimmedFloat,
+				trimmedFloat.length - 1,
+			);
+		default:
+			return new ScientificNotation(
+				trimmedFloat.replace(".", ""),
+				indexOfDecimalPoint - 1,
+			);
+	}
+}
+
+/**
+ * Converts a base ten number to proper scientific notation
+ * @param {string} stringNumber the string representation of the base ten number to be converted
+ * @param {boolean} parseAsFloat if true, the coefficient will be always parsed as a float, regardless of whether a decimal point is present
+ * @returns {ScientificNotation} the object containing the number's coefficient and order of magnitude
+ */
+function convertNumberToScientificNotation(stringNumber, parseAsFloat) {
+	const splitNumber = stringNumber.split("e");
+	const originalCoefficient = splitNumber[0];
+	const normalizedNumber =
+		parseAsFloat || stringNumber.includes(".")
+			? normalizeFloat(originalCoefficient)
+			: normalizeInteger(originalCoefficient);
+	if (splitNumber.length > 1) {
+		normalizedNumber.magnitude += parseInt(splitNumber[1], 10);
+	}
+
+	return normalizedNumber;
+}
+
+/**
+ * Checks that the user-intended base ten number equals the actual number after is has been converted to the Number type
+ * @param {Node} node the node being evaluated
+ * @returns {boolean} true if they do not match
+ */
+function baseTenLosesPrecision(node) {
+	const rawNumber = getRaw(node).toLowerCase();
+	const normalizedRawNumber = convertNumberToScientificNotation(
+		rawNumber,
+		false,
+	);
+	const requestedPrecision = normalizedRawNumber.coefficient.length;
+
+	if (requestedPrecision > 100) {
+		return true;
+	}
+	const storedNumber = node.value.toPrecision(requestedPrecision);
+	const normalizedStoredNumber = convertNumberToScientificNotation(
+		storedNumber,
+		true,
+	);
+
+	return (
+		normalizedRawNumber.magnitude !== normalizedStoredNumber.magnitude ||
+		normalizedRawNumber.coefficient !== normalizedStoredNumber.coefficient
+	);
+}
+
+/**
+ * Checks that the user-intended number equals the actual number after is has been converted to the Number type
+ * @param {Node} node the node being evaluated
+ * @returns {boolean} true if they do not match
+ */
+function losesPrecision(node) {
+	return isBaseTen(node)
+		? baseTenLosesPrecision(node)
+		: notBaseTenLosesPrecision(node);
+}
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../types').Rule.RuleModule} */
+module.exports = {
+	meta: {
+		type: "problem",
+		dialects: ["typescript", "javascript"],
+		language: "javascript",
+
+		docs: {
+			description: "Disallow literal numbers that lose precision",
+			recommended: true,
+			url: "https://eslint.org/docs/latest/rules/no-loss-of-precision",
+		},
+		schema: [],
+		messages: {
+			noLossOfPrecision:
+				"This number literal will lose precision at runtime.",
+		},
+	},
+
+	create(context) {
+		return {
+			Literal(node) {
+				if (node.value && isNumber(node) && losesPrecision(node)) {
+					context.report({
+						messageId: "noLossOfPrecision",
+						node,
+					});
+				}
+			},
+		};
+	},
+};