node html 模块,CommonJS 模块

柔情只为你懂 2022-08-31 01:00 176阅读 0赞

总结

要获取调用 require() 时将加载的确切文件名，则使用 require.resolve() 函数。

综上所述，这里是 require() 的伪代码高级算法：

require(X) from module at path Y

1. If X is a core module,

a. return the core module

b. STOP

2. If X begins with '/'

a. set Y to be the filesystem root

3. If X begins with './' or '/' or '../'

a. LOAD\_AS\_FILE(Y + X)

b. LOAD\_AS\_DIRECTORY(Y + X)

c. THROW "not found"

4. If X begins with '\#'

a. LOAD\_PACKAGE\_IMPORTS(X, dirname(Y))

5. LOAD\_PACKAGE\_SELF(X, dirname(Y))

6. LOAD\_NODE\_MODULES(X, dirname(Y))

7. THROW "not found"

LOAD\_AS\_FILE(X)

1. If X is a file, load X as its file extension format. STOP

2. If X.js is a file, load X.js as JavaScript text. STOP

3. If X.json is a file, parse X.json to a JavaScript Object. STOP

4. If X.node is a file, load X.node as binary addon. STOP

LOAD\_INDEX(X)

1. If X/index.js is a file, load X/index.js as JavaScript text. STOP

2. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP

3. If X/index.node is a file, load X/index.node as binary addon. STOP

LOAD\_AS\_DIRECTORY(X)

1. If X/package.json is a file,

a. Parse X/package.json, and look for "main" field.

b. If "main" is a falsy value, GOTO 2.

c. let M = X + (json main field)

d. LOAD\_AS\_FILE(M)

e. LOAD\_INDEX(M)

f. LOAD\_INDEX(X) DEPRECATED

g. THROW "not found"

2. LOAD\_INDEX(X)

LOAD\_NODE\_MODULES(X, START)

1. let DIRS = NODE\_MODULES\_PATHS(START)

2. for each DIR in DIRS:

a. LOAD\_PACKAGE\_EXPORTS(X, DIR)

b. LOAD\_AS\_FILE(DIR/X)

c. LOAD\_AS\_DIRECTORY(DIR/X)

NODE\_MODULES\_PATHS(START)

1. let PARTS = path split(START)

2. let I = count of PARTS - 1

3. let DIRS = \[GLOBAL\_FOLDERS\]

4. while I >= 0,

a. if PARTS\[I\] = "node\_modules" CONTINUE

b. DIR = path join(PARTS\[0 .. I\] + "node\_modules")

c. DIRS = DIRS + DIR

d. let I = I - 1

5. return DIRS

LOAD\_PACKAGE\_IMPORTS(X, DIR)

1. Find the closest package scope SCOPE to DIR.

2. If no scope was found, return.

3. If the SCOPE/package.json "imports" is null or undefined, return.

4. let MATCH = PACKAGE\_IMPORTS\_RESOLVE(X, pathToFileURL(SCOPE),

\["node", "require"\]) defined in the ESM resolver.

5. RESOLVE\_ESM\_MATCH(MATCH).

LOAD\_PACKAGE\_EXPORTS(X, DIR)

1. Try to interpret X as a combination of NAME and SUBPATH where the name

may have a @scope/ prefix and the subpath begins with a slash (\`/\`).

2. If X does not match this pattern or DIR/NAME/package.json is not a file,

return.

3. Parse DIR/NAME/package.json, and look for "exports" field.

4. If "exports" is null or undefined, return.

5. let MATCH = PACKAGE\_EXPORTS\_RESOLVE(pathToFileURL(DIR/NAME), "." + SUBPATH,

\`package.json\` "exports", \["node", "require"\]) defined in the ESM resolver.

6. RESOLVE\_ESM\_MATCH(MATCH)

LOAD\_PACKAGE\_SELF(X, DIR)

1. Find the closest package scope SCOPE to DIR.

2. If no scope was found, return.

3. If the SCOPE/package.json "exports" is null or undefined, return.

4. If the SCOPE/package.json "name" is not the first segment of X, return.

5. let MATCH = PACKAGE\_EXPORTS\_RESOLVE(pathToFileURL(SCOPE),

"." + X.slice("name".length), \`package.json\` "exports", \["node", "require"\])

defined in the ESM resolver.

6. RESOLVE\_ESM\_MATCH(MATCH)

RESOLVE\_ESM\_MATCH(MATCH)

1. let \{ RESOLVED, EXACT \} = MATCH

2. let RESOLVED\_PATH = fileURLToPath(RESOLVED)

3. If EXACT is true,

a. If the file at RESOLVED\_PATH exists, load RESOLVED\_PATH as its extension

format. STOP

4. Otherwise, if EXACT is false,

a. LOAD\_AS\_FILE(RESOLVED\_PATH)

b. LOAD\_AS\_DIRECTORY(RESOLVED\_PATH)

5. THROW "not found"

node html 模块,CommonJS 模块

发表评论取消回复

还没有评论，来说两句吧...

相关阅读

相关【JavaScript模块化】2-CommonJS_Node模块化教程

相关浏览 Node.js 模块系统：CommonJS 与使用 TypeScript 的 ES 模块

相关 CommonJs模块规范和ES6模块规范

相关 JS模块化2_CommonJS_Node模块化教程

相关 node html 模块,CommonJS 模块

相关 ES6 模块与 CommonJS 模块的差异

相关模块化 CommonJS规范

相关【Node.js和模块化】CommonJS

相关 ES6模块和CommonJS模块相互转换

相关 CommonJS的模块规范