eslint/lib/rules/func-call-spacing.js

/**
 * @fileoverview Rule to control spacing within function calls
 * @author Matt DuVall <http://www.mattduvall.com>
 */

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const astUtils = require("./utils/ast-utils");

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

module.exports = {
    meta: {
        type: "layout",

        docs: {
            description: "require or disallow spacing between function identifiers and their invocations",
            category: "Stylistic Issues",
            recommended: false,
            url: "https://eslint.org/docs/rules/func-call-spacing"
        },

        fixable: "whitespace",

        schema: {
            anyOf: [
                {
                    type: "array",
                    items: [
                        {
                            enum: ["never"]
                        }
                    ],
                    minItems: 0,
                    maxItems: 1
                },
                {
                    type: "array",
                    items: [
                        {
                            enum: ["always"]
                        },
                        {
                            type: "object",
                            properties: {
                                allowNewlines: {
                                    type: "boolean"
                                }
                            },
                            additionalProperties: false
                        }
                    ],
                    minItems: 0,
                    maxItems: 2
                }
            ]
        },

        messages: {
            unexpectedWhitespace: "Unexpected whitespace between function name and paren.",
            unexpectedNewline: "Unexpected newline between function name and paren.",
            missing: "Missing space between function name and paren."
        }
    },

    create(context) {

        const never = context.options[0] !== "always";
        const allowNewlines = !never && context.options[1] && context.options[1].allowNewlines;
        const sourceCode = context.getSourceCode();
        const text = sourceCode.getText();

        /**
         * Check if open space is present in a function name
         * @param {ASTNode} node node to evaluate
         * @param {Token} leftToken The last token of the callee. This may be the closing parenthesis that encloses the callee.
         * @param {Token} rightToken Tha first token of the arguments. this is the opening parenthesis that encloses the arguments.
         * @returns {void}
         * @private
         */
        function checkSpacing(node, leftToken, rightToken) {
            const textBetweenTokens = text.slice(leftToken.range[1], rightToken.range[0]).replace(/\/\*.*?\*\//gu, "");
            const hasWhitespace = /\s/u.test(textBetweenTokens);
            const hasNewline = hasWhitespace && astUtils.LINEBREAK_MATCHER.test(textBetweenTokens);

            /*
             * never allowNewlines hasWhitespace hasNewline message
             * F     F             F             F          Missing space between function name and paren.
             * F     F             F             T          (Invalid `!hasWhitespace && hasNewline`)
             * F     F             T             T          Unexpected newline between function name and paren.
             * F     F             T             F          (OK)
             * F     T             T             F          (OK)
             * F     T             T             T          (OK)
             * F     T             F             T          (Invalid `!hasWhitespace && hasNewline`)
             * F     T             F             F          Missing space between function name and paren.
             * T     T             F             F          (Invalid `never && allowNewlines`)
             * T     T             F             T          (Invalid `!hasWhitespace && hasNewline`)
             * T     T             T             T          (Invalid `never && allowNewlines`)
             * T     T             T             F          (Invalid `never && allowNewlines`)
             * T     F             T             F          Unexpected space between function name and paren.
             * T     F             T             T          Unexpected space between function name and paren.
             * T     F             F             T          (Invalid `!hasWhitespace && hasNewline`)
             * T     F             F             F          (OK)
             *
             * T                   T                        Unexpected space between function name and paren.
             * F                   F                        Missing space between function name and paren.
             * F     F                           T          Unexpected newline between function name and paren.
             */

            if (never && hasWhitespace) {
                context.report({
                    node,
                    loc: {
                        start: leftToken.loc.end,
                        end: {
                            line: rightToken.loc.start.line,
                            column: rightToken.loc.start.column - 1
                        }
                    },
                    messageId: "unexpectedWhitespace",
                    fix(fixer) {

                        // Don't remove comments.
                        if (sourceCode.commentsExistBetween(leftToken, rightToken)) {
                            return null;
                        }

                        // If `?.` exists, it doesn't hide no-unexpected-multiline errors
                        if (node.optional) {
                            return fixer.replaceTextRange([leftToken.range[1], rightToken.range[0]], "?.");
                        }

                        /*
                         * Only autofix if there is no newline
                         * https://github.com/eslint/eslint/issues/7787
                         */
                        if (hasNewline) {
                            return null;
                        }
                        return fixer.removeRange([leftToken.range[1], rightToken.range[0]]);
                    }
                });
            } else if (!never && !hasWhitespace) {
                context.report({
                    node,
                    loc: {
                        start: {
                            line: leftToken.loc.end.line,
                            column: leftToken.loc.end.column - 1
                        },
                        end: rightToken.loc.start
                    },
                    messageId: "missing",
                    fix(fixer) {
                        if (node.optional) {
                            return null; // Not sure if inserting a space to either before/after `?.` token.
                        }
                        return fixer.insertTextBefore(rightToken, " ");
                    }
                });
            } else if (!never && !allowNewlines && hasNewline) {
                context.report({
                    node,
                    loc: {
                        start: leftToken.loc.end,
                        end: rightToken.loc.start
                    },
                    messageId: "unexpectedNewline",
                    fix(fixer) {

                        /*
                         * Only autofix if there is no newline
                         * https://github.com/eslint/eslint/issues/7787
                         * But if `?.` exists, it doesn't hide no-unexpected-multiline errors
                         */
                        if (!node.optional) {
                            return null;
                        }

                        // Don't remove comments.
                        if (sourceCode.commentsExistBetween(leftToken, rightToken)) {
                            return null;
                        }

                        const range = [leftToken.range[1], rightToken.range[0]];
                        const qdToken = sourceCode.getTokenAfter(leftToken);

                        if (qdToken.range[0] === leftToken.range[1]) {
                            return fixer.replaceTextRange(range, "?. ");
                        }
                        if (qdToken.range[1] === rightToken.range[0]) {
                            return fixer.replaceTextRange(range, " ?.");
                        }
                        return fixer.replaceTextRange(range, " ?. ");
                    }
                });
            }
        }

        return {
            "CallExpression, NewExpression"(node) {
                const lastToken = sourceCode.getLastToken(node);
                const lastCalleeToken = sourceCode.getLastToken(node.callee);
                const parenToken = sourceCode.getFirstTokenBetween(lastCalleeToken, lastToken, astUtils.isOpeningParenToken);
                const prevToken = parenToken && sourceCode.getTokenBefore(parenToken, astUtils.isNotQuestionDotToken);

                // Parens in NewExpression are optional
                if (!(parenToken && parenToken.range[1] < node.range[1])) {
                    return;
                }

                checkSpacing(node, prevToken, parenToken);
            },

            ImportExpression(node) {
                const leftToken = sourceCode.getFirstToken(node);
                const rightToken = sourceCode.getTokenAfter(leftToken);

                checkSpacing(node, leftToken, rightToken);
            }
        };

    }
};