我尝试尽可能减少 JavaScript 以使其加载速度更快。我的最后一步是合成相互跟随的
const
和 let
。 (所有注释、空格、换行符等均已使用正则表达式删除)。
const
的示例(let
将是相同的):
const abc='mystring';const def=[1,2,3];def.forEach(function(){doThis(i)};const ghi='123';function doThis(){...}
| const#1 | const#2 | something else | const#3 | ...
我为找到的每个
const
创建一个数组
let rgx = /const\s+([\w]+)\s*=\s*(.*?)(?=\;)/g; // from 'const' to ';'
let arr = mycode.match(rgx); // mycode = value of the textarea containing the code
[0] const abc='mystring'
[1] const def=[1,2,3]
[2] const ghi='123'
一旦找到所有
const
,我就会寻找它们的位置和长度
for (let i=0; i<arr.length; i++){
let pos = mycode.indexOf(arr[i]+';'); // add the ';'
console.log(pos+' + '+(arr[i].length+1)+' = '+(pos+(arr[i].length)+1))
}
0 + 21 = 21 // const abc='mystring'; = length 21
21 + 18 = 49 // const def=[1,2,3]; = length 18
68 + 13 = 81 // const ghi='123'; = length 13
21 作为 pos+length(第 1 行)的结果,21 作为 pos(第 2 行)意味着
arr[1]
跟随 arr[0]
并且
49 -> 68 表示此 const
不应受到影响,因为它后面没有其他 const
。
我想要实现的是
const abc='mystring',def=[1,2,3];def.forEach(function(){doThis(i)};const ghi='123';
| const #1,#2 | ... | const#3 |
与
replace(";"+arr[1].susbstr(0,6),",")
...
我尝试使用 [pos]+[lengths] 的数组
vals
,如果 vals[i][0]==vals[i-1][1]
那么两个 const 相互跟随,但这有点麻烦,最重要的是,如果我有 3 个,我该如何管理这个或者 4 个常量一个在另一个后面?有没有一种方法可以实现这个结果,例如,知道可能有 3 个 const,然后是一个函数,然后 2 个 let,然后 3 个 cons,然后...?
要实现
const
和let
声明的合并,您可以按照以下步骤操作:
const
和 let
声明,并将它们存储在单独的数组中。我分享了一个演示这些步骤的代码片段:
// Sample JavaScript code
let code = "const abc='mystring';const def=[1,2,3];def.forEach(function(){doThis(i)});const ghi='123';let x = 10;let y = 20;const z = 'hello';";
// Step 1: Find all const and let declarations
let constRegex = /const\s+([\w]+)\s*=\s*(.*?)(?=;)/g;
let letRegex = /let\s+([\w]+)\s*=\s*(.*?)(?=;)/g;
let constDeclarations = code.match(constRegex) || [];
let letDeclarations = code.match(letRegex) || [];
// Step 2: Determine positions and lengths of declarations
let getDeclarationPositions = (declarations) => {
return declarations.map(declaration => {
let pos = code.indexOf(declaration);
return [pos, declaration.length];
});
};
let constPositions = getDeclarationPositions(constDeclarations);
let letPositions = getDeclarationPositions(letDeclarations);
// Step 3: Check if consecutive declarations follow each other
let consolidateDeclarations = (positions) => {
let consolidated = [];
let start = 0;
for (let i = 1; i < positions.length; i++) {
if (positions[i][0] === positions[i - 1][0] + positions[i - 1][1] + 1) {
continue;
} else {
consolidated.push(positions.slice(start, i));
start = i;
}
}
consolidated.push(positions.slice(start));
return consolidated;
};
let consolidatedConst = consolidateDeclarations(constPositions);
let consolidatedLet = consolidateDeclarations(letPositions);
// Step 4: Consolidate consecutive declarations into single lines
let consolidateIntoSingleLine = (declarations, type) => {
return declarations.map(declarationGroup => {
let start = declarationGroup[0][0];
let end = declarationGroup[declarationGroup.length - 1][0] + declarationGroup[declarationGroup.length - 1][1];
let consolidatedDeclaration = code.substring(start, end);
return consolidatedDeclaration.replace(/;/g, ',');
}).join(';');
};
let consolidatedConstLine = consolidateIntoSingleLine(consolidatedConst, 'const');
let consolidatedLetLine = consolidateIntoSingleLine(consolidatedLet, 'let');
console.log('Consolidated Const:', consolidatedConstLine);
console.log('Consolidated Let:', consolidatedLetLine);
此代码将把连续的 const 和 let 声明合并到以逗号分隔的单行中。您可以根据您的具体要求或边缘情况进一步完善它。