TypeScript Op.nonNull函數代碼示例

export function renderModuleDeclaration(_: ModuleDeclaration): void {
	setAst(_)

	if (_ instanceof ImportDeclaration)
		renderImportDeclarationNoLoc(_)

	else if (_ instanceof ExportNamedDeclaration) {
		const {declaration, specifiers, source} = _
		o('export ')
		if (nonNull(declaration))
			renderDeclaration(declaration)
		else {
			o('{')
			interleave(specifiers, renderExportSpecifier, ',')
			o('}')
			if (nonNull(source)) {
				o(' from ')
				renderLiteralString(source)
			}
		}

	} else if (_ instanceof ExportDefaultDeclaration) {
		o('export default ')
		renderDeclarationOrExpression(_.declaration)

	} else if (_ instanceof ExportAllDeclaration) {
		o('export * from ')
		renderLiteralString(_.source)

	} else
		throw badType(_)
}

export function renderContinueStatementNoLoc({label}: ContinueStatement): void {
	o('continue')
	if (nonNull(label)) {
		o(' ')
		renderIdentifier(label)
	}
}

export function renderBreakStatementNoLoc({label}: BreakStatement): void {
	o('break')
	if (nonNull(label)) {
		o(' ')
		renderIdentifier(label)
	}
}

/** Parse a [[Name]] or a [[Keyword]] usable as one. */
export default function parseName(token: Token): string {
	const name = tryParseName(token)
	if (nonNull(name))
		return name
	else
		throw unexpected(token)
}

export function maybeWrapInCheckInstance(
	ast: Expression,
	opType: Op<Val>,
	name: string)
	: Expression {
	return compileOptions.checks && nonNull(opType) ?
		msCall('checkInstance', transpileVal(opType), ast, new LiteralString(name)) :
		ast
}

export function renderVariableDeclarator(_: VariableDeclarator): void {
	setAst(_)
	const {id, init} = _
	renderPattern(id)
	if (nonNull(init)) {
		o('=')
		renderExpression(init)
	}
}

export function renderLoopNoLoc(_: Loop): void {
	if (_ instanceof WhileStatement) {
		const {test, body} = _
		o('while(')
		renderExpression(test)
		o(')')
		renderStatement(body)

	} else if (_ instanceof DoWhileStatement) {
		const {body, test} = _
		o('do ')
		renderStatement(body)
		if (!(body instanceof BlockStatement))
			o(';')
		o(' while(')
		renderExpression(test)
		o(')')

	} else if (_ instanceof ForStatement) {
		const {init, test, update, body} = _
		o('for(')
		if (nonNull(init))
			renderVariableDeclarationOrExpression(init)
		o(';')
		if (nonNull(test))
			renderExpression(test)
		o(';')
		if (nonNull(update))
			renderExpression(update)
		o(')')
		renderStatement(body)

	} else if (_ instanceof ForInOfStatement) {
		o('for(')
		renderVariableDeclarationOrIdentifier(_.left)
		o(_ instanceof ForOfStatement ? ' of ' : ' in ')
		renderExpression(_.right)
		o(')')
		renderStatement(_.body)

	} else
		throw badType(_)
}

/** Parse a plain member (`a.b`) or computed member (`a."b"`). */
export default function parseMemberName(token: Token): MemberName {
	const name = tryParseName(token)
	if (nonNull(name)) // .foo
		return name
	else if (token instanceof GroupQuote) // ."foo"
		return parseQuote(Slice.of(token))
	else if (token instanceof GroupParenthesis) // .(foo)
		return parseExpr(Tokens.of(token))
	else
		throw unexpected(token)
}

export function renderFunctionNoLoc(_: FunctionDeclaration | FunctionExpression): void {
	const {id, params, body, async, generator} = _
	if (async)
		o('async ')
	o('function')
	if (generator)
		o('*')
	if (nonNull(id)) {
		o(' ')
		renderIdentifier(id)
	}
	paren(params, renderPattern)
	renderBlockStatement(body)
}

function mapStr(str: string): void {
	if (curAst !== lastMappedAst) {
		const {loc} = curAst
		if (nonNull(loc)) {
			sourceMap.addMapping({
				source: inFilePath,
				original: loc.start,
				generated: new Pos(outLine, outColumn)
			})
			lastMappedAst = curAst
		}
	}
	outColumn = outColumn + str.length
}