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A tag function that removes leading spaces until a line reaches the left margin.
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| // MIT License | |
| // | |
| // Copyright (c) 2023 Maël Obréjan | |
| // | |
| // Permission is hereby granted, free of charge, to any person obtaining a copy | |
| // of this software and associated documentation files (the "Software"), to deal | |
| // in the Software without restriction, including without limitation the rights | |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| // copies of the Software, and to permit persons to whom the Software is | |
| // furnished to do so, subject to the following conditions: | |
| // | |
| // The above copyright notice and this permission notice shall be included in all | |
| // copies or substantial portions of the Software. | |
| // | |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| // SOFTWARE. | |
| // A tag function that removes leading spaces until a line reaches the left margin. | |
| function dedent(strings, ...values) => { | |
| let lines = String.raw({ raw: strings }, ...values).split("\n"); | |
| const minIdent = Math.min( | |
| ...lines | |
| .map((line) => [line, line.replace(/^ +/, "")]) | |
| .filter(([_, trimmedLine]) => trimmedLine.length > 0) | |
| .map(([line, trimmedLine]) => line.length - trimmedLine.length), | |
| ); | |
| return lines.map((line) => line.slice(minIdent)).join("\n"); | |
| } | |
| // A cached version for better performance when repeatedly formatting the same template with different parameters. | |
| function dedentCached(strings, ...values) { | |
| const self = dedentCached; | |
| self.cache ??= new Map(); | |
| if (!self.cache.has(strings)) { | |
| const lines = strings | |
| .reduce((buf, slice) => { | |
| let [line, ...lines] = buf; | |
| for (const end of slice.split("\n")) { | |
| lines = [[...(line ?? []), end], ...lines]; | |
| line = undefined; | |
| } | |
| return lines; | |
| }, []) | |
| .reverse(); | |
| const minIndent = Math.min( | |
| ...lines | |
| .map(([line]) => [line, line.replace(/^ +/, "")]) | |
| .filter(([_, trimmedLine]) => trimmedLine.length > 0) | |
| .map(([line, trimmedLine]) => line.length - trimmedLine.length), | |
| ); | |
| self.cache.set( | |
| strings, | |
| lines | |
| .map(([start, ...rest]) => [start.slice(minIndent), ...rest]) | |
| .reduce(([end, ...buf], [start, ...rest]) => [ | |
| ...rest.reverse(), | |
| `${end}\n${start}`, | |
| ...buf, | |
| ]) | |
| .reverse(), | |
| ); | |
| } | |
| return String.raw({ raw: self.cache.get(strings) }, ...values); | |
| } |
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