1 | export abstract class _CodeOrName {
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2 | abstract readonly str: string
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3 | abstract readonly names: UsedNames
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4 | abstract toString(): string
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5 | abstract emptyStr(): boolean
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6 | }
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7 |
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8 | export const IDENTIFIER = /^[a-z$_][a-z$_0-9]*$/i
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9 |
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10 | export class Name extends _CodeOrName {
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11 | readonly str: string
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12 | constructor(s: string) {
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13 | super()
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14 | if (!IDENTIFIER.test(s)) throw new Error("CodeGen: name must be a valid identifier")
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15 | this.str = s
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16 | }
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17 |
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18 | toString(): string {
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19 | return this.str
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20 | }
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21 |
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22 | emptyStr(): boolean {
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23 | return false
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24 | }
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25 |
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26 | get names(): UsedNames {
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27 | return {[this.str]: 1}
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28 | }
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29 | }
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30 |
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31 | export class _Code extends _CodeOrName {
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32 | readonly _items: readonly CodeItem[]
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33 | private _str?: string
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34 | private _names?: UsedNames
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35 |
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36 | constructor(code: string | readonly CodeItem[]) {
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37 | super()
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38 | this._items = typeof code === "string" ? [code] : code
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39 | }
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40 |
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41 | toString(): string {
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42 | return this.str
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43 | }
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44 |
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45 | emptyStr(): boolean {
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46 | if (this._items.length > 1) return false
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47 | const item = this._items[0]
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48 | return item === "" || item === '""'
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49 | }
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50 |
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51 | get str(): string {
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52 | return (this._str ??= this._items.reduce((s: string, c: CodeItem) => `${s}${c}`, ""))
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53 | }
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54 |
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55 | get names(): UsedNames {
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56 | return (this._names ??= this._items.reduce((names: UsedNames, c) => {
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57 | if (c instanceof Name) names[c.str] = (names[c.str] || 0) + 1
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58 | return names
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59 | }, {}))
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60 | }
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61 | }
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62 |
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63 | export type CodeItem = Name | string | number | boolean | null
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64 |
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65 | export type UsedNames = Record<string, number | undefined>
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66 |
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67 | export type Code = _Code | Name
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68 |
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69 | export type SafeExpr = Code | number | boolean | null
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70 |
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71 | export const nil = new _Code("")
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72 |
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73 | type CodeArg = SafeExpr | string | undefined
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74 |
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75 | export function _(strs: TemplateStringsArray, ...args: CodeArg[]): _Code {
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76 | const code: CodeItem[] = [strs[0]]
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77 | let i = 0
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78 | while (i < args.length) {
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79 | addCodeArg(code, args[i])
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80 | code.push(strs[++i])
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81 | }
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82 | return new _Code(code)
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83 | }
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84 |
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85 | const plus = new _Code("+")
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86 |
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87 | export function str(strs: TemplateStringsArray, ...args: (CodeArg | string[])[]): _Code {
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88 | const expr: CodeItem[] = [safeStringify(strs[0])]
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89 | let i = 0
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90 | while (i < args.length) {
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91 | expr.push(plus)
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92 | addCodeArg(expr, args[i])
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93 | expr.push(plus, safeStringify(strs[++i]))
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94 | }
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95 | optimize(expr)
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96 | return new _Code(expr)
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97 | }
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98 |
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99 | export function addCodeArg(code: CodeItem[], arg: CodeArg | string[]): void {
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100 | if (arg instanceof _Code) code.push(...arg._items)
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101 | else if (arg instanceof Name) code.push(arg)
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102 | else code.push(interpolate(arg))
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103 | }
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104 |
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105 | function optimize(expr: CodeItem[]): void {
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106 | let i = 1
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107 | while (i < expr.length - 1) {
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108 | if (expr[i] === plus) {
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109 | const res = mergeExprItems(expr[i - 1], expr[i + 1])
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110 | if (res !== undefined) {
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111 | expr.splice(i - 1, 3, res)
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112 | continue
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113 | }
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114 | expr[i++] = "+"
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115 | }
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116 | i++
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117 | }
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118 | }
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119 |
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120 | function mergeExprItems(a: CodeItem, b: CodeItem): CodeItem | undefined {
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121 | if (b === '""') return a
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122 | if (a === '""') return b
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123 | if (typeof a == "string") {
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124 | if (b instanceof Name || a[a.length - 1] !== '"') return
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125 | if (typeof b != "string") return `${a.slice(0, -1)}${b}"`
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126 | if (b[0] === '"') return a.slice(0, -1) + b.slice(1)
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127 | return
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128 | }
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129 | if (typeof b == "string" && b[0] === '"' && !(a instanceof Name)) return `"${a}${b.slice(1)}`
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130 | return
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131 | }
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132 |
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133 | export function strConcat(c1: Code, c2: Code): Code {
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134 | return c2.emptyStr() ? c1 : c1.emptyStr() ? c2 : str`${c1}${c2}`
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135 | }
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136 |
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137 | // TODO do not allow arrays here
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138 | function interpolate(x?: string | string[] | number | boolean | null): SafeExpr | string {
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139 | return typeof x == "number" || typeof x == "boolean" || x === null
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140 | ? x
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141 | : safeStringify(Array.isArray(x) ? x.join(",") : x)
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142 | }
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143 |
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144 | export function stringify(x: unknown): Code {
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145 | return new _Code(safeStringify(x))
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146 | }
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147 |
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148 | export function safeStringify(x: unknown): string {
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149 | return JSON.stringify(x)
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150 | .replace(/\u2028/g, "\\u2028")
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151 | .replace(/\u2029/g, "\\u2029")
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152 | }
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153 |
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154 | export function getProperty(key: Code | string | number): Code {
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155 | return typeof key == "string" && IDENTIFIER.test(key) ? new _Code(`.${key}`) : _`[${key}]`
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156 | }
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157 |
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158 | //Does best effort to format the name properly
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159 | export function getEsmExportName(key: Code | string | number): Code {
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160 | if (typeof key == "string" && IDENTIFIER.test(key)) {
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161 | return new _Code(`${key}`)
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162 | }
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163 | throw new Error(`CodeGen: invalid export name: ${key}, use explicit $id name mapping`)
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164 | }
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165 |
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166 | export function regexpCode(rx: RegExp): Code {
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167 | return new _Code(rx.toString())
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168 | }
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169 |
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