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/
numberLiteralFormatRule.ts
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/
numberLiteralFormatRule.ts
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/**
* @license
* Copyright 2017 Palantir Technologies, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { isNumericLiteral } from "tsutils";
import * as ts from "typescript";
import * as Lint from "../index";
import { isUpperCase } from "../utils";
export class Rule extends Lint.Rules.AbstractRule {
/* tslint:disable:object-literal-sort-keys */
public static metadata: Lint.IRuleMetadata = {
ruleName: "number-literal-format",
hasFix: true,
description:
"Checks that decimal literals should begin with '0.' instead of just '.', and should not end with a trailing '0'.",
optionsDescription: "Not configurable.",
options: null,
optionExamples: [true],
rationale: Lint.Utils.dedent`
Helps keep a consistent style with numeric literals.
Non-standard literals are more difficult to scan through and can be a symptom of typos.
`,
type: "style",
typescriptOnly: false,
};
/* tslint:enable:object-literal-sort-keys */
public static FAILURE_STRING_LEADING_0 = "Number literal should not have a leading '0'.";
public static FAILURE_STRING_TRAILING_0 = "Number literal should not have a trailing '0'.";
public static FAILURE_STRING_TRAILING_DECIMAL = "Number literal should not end in '.'.";
public static FAILURE_STRING_LEADING_DECIMAL =
"Number literal should begin with '0.' and not just '.'.";
public static FAILURE_STRING_NOT_UPPERCASE = "Hexadecimal number literal should be uppercase.";
public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
return this.applyWithFunction(sourceFile, walk);
}
}
function walk(ctx: Lint.WalkContext<void>): void {
const { sourceFile } = ctx;
return ts.forEachChild(sourceFile, function cb(node: ts.Node): void {
if (isNumericLiteral(node)) {
return check(node);
}
return ts.forEachChild(node, cb);
});
function check(node: ts.NumericLiteral): void {
// Apparently the number literal '0.0' has a '.text' of '0', so use '.getText()' instead.
const text = node.getText(sourceFile);
const start = node.getStart();
if (text.length <= 1) {
return;
}
if (text.startsWith("0")) {
// Hex/octal/binary number can't have decimal point or exponent, so no other errors possible.
switch (text[1]) {
case "x":
// strip "0x"
const hexNumber = text.slice(2);
if (!isUpperCase(hexNumber)) {
ctx.addFailureAtNode(
node,
Rule.FAILURE_STRING_NOT_UPPERCASE,
Lint.Replacement.replaceNode(node, `0x${hexNumber.toUpperCase()}`),
);
}
return;
case "o":
case "b":
return;
case ".":
break;
default:
ctx.addFailureAtNode(
node,
Rule.FAILURE_STRING_LEADING_0,
Lint.Replacement.deleteFromTo(start, start + /^0+/.exec(text)![0].length),
);
return;
}
}
const [num, exp = ""] = text.split(/e/i);
const [integer, float = ""] = num.split(".");
const matchedNumeric = /(\.)([1-9]*)(0+)/.exec(num);
const [dot = "", numbers = "", zeroes = ""] = Array.isArray(matchedNumeric)
? matchedNumeric.slice(1)
: [];
if (exp.startsWith("-0") || exp.startsWith("0")) {
const expStart = start + num.length + 1; // position of exp part
const expNumberStart = /\D/.test(exp.charAt(0)) ? expStart + 1 : expStart; // do not remove "-" or "+"
ctx.addFailureAt(
node.getEnd() - exp.length,
exp.length,
Rule.FAILURE_STRING_LEADING_0,
Lint.Replacement.deleteFromTo(
expNumberStart,
expNumberStart + /0+/.exec(exp)![0].length,
),
);
}
if (!num.includes(".")) {
return;
}
if (num.startsWith(".")) {
// .1 -> 0.1
fail(Rule.FAILURE_STRING_LEADING_DECIMAL, Lint.Replacement.appendText(start, "0"));
} else if (num.endsWith(".")) {
// 1. -> 1
fail(
Rule.FAILURE_STRING_TRAILING_DECIMAL,
Lint.Replacement.deleteText(start + num.length - 1, 1),
);
}
// Allow '10', but not '1.0'
if (float.endsWith("0")) {
// 1.0 -> 1
const offset = numbers.length > 0 ? dot.length + numbers.length : 0;
const length = (numbers.length > 0 ? 0 : dot.length) + zeroes.length;
fail(
Rule.FAILURE_STRING_TRAILING_0,
Lint.Replacement.deleteText(start + integer.length + offset, length),
);
}
function fail(message: string, fix?: Lint.Replacement | Lint.Replacement[]): void {
ctx.addFailureAt(node.getStart(sourceFile), num.length, message, fix);
}
}
}